JP4595078B2 - Apparatus and method for estimating three-dimensional distribution of rainfall intensity and amount of rainwater - Google Patents
Apparatus and method for estimating three-dimensional distribution of rainfall intensity and amount of rainwater Download PDFInfo
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Description
本発明は、マルチパラメータレーダにより得られる比偏波間位相差KDP、反射因子差ZDR、反射因子ZH に基づき降雨強度と雨水量の3次元分布を推定する降雨強度と雨水量の3次元分布推定法及び装置に関する。 The present invention estimates the three-dimensional distribution of the rainfall intensity and the amount of rain water based on the phase difference K DP , the reflection factor difference Z DR and the reflection factor Z H obtained by the multi-parameter radar. The present invention relates to a distribution estimation method and apparatus.
降雨強度や雨水量の3次元分布、鉛直積算雨水量の2次元分布を知ることは降水システムの構造や発生・発達のメカニズムを調べる上で、また、災害をもたらすような豪雨の短時間予測にとって重要である。気象レーダはこのような目的には有効な観測機器である。国土交通省では、全国に約40台の在来型レーダと呼ばれる気象レーダを配置し降雨の監視と予測に利用している。このレーダシステムでは、1種類の電波をアンテナから大気中へ射出することにより、射出された電波が雨に当たってレーダアンテナへ帰ってくるので、電波の強さを測定して、その時間から雨の位置を推定し、反射因子Zと呼ばれる情報から降雨強度Rや雨水量Mを推定している。降雨強度や雨水量の3次元分布は、アンテナの仰角を変化させて観測することにより求めることができる。その際、Z−R関係式、Z−M関係式と呼ばれる経験式が用いられる。この関係式は、レーダハードウエアのキャリブレーション、降雨タイプに依存する、降雨減衰の影響を受けるなどの様々な誤差要因のために、精度良い測定をおこなうことは困難であることが良く知られている。 在来型レーダを用いた降雨強度や雨水量の推定方法に対して、偏波レーダを用いた降雨強度や雨水量の推定方法が提案されている(例えば、特許文献1、2参照)。これらの方法では、偏波レーダから求まる反射因子ZH と反射因子差ZDRを用いることにより、降雨強度や雨水量を精度良く推定しようとするものである。偏波レーダから得られる反射因子ZH と反射因子差ZDRを用いる降雨強度や雨水量の推定方法は、理論的には精度の良い推定方法であるが、波長の短い偏波レーダでは、反射因子ZH と反射因子差ZDRは降雨による減衰の影響を受けるために、前記在来型レーダの場合と同様に、豪雨時の計測では大きな誤差を伴う場合がある。
在来型レーダを用いた降雨強度や雨水量の推定方法は、レーダのキャリブレーション誤差、降雨減衰、雨滴粒径分布の変動といった様々な誤差要因のために降雨強度の推定精度は良くない。そこで、気象庁などでは、地上に設置した雨量計のデータで推定値を補正することで精度の向上を図っているが、利用できる雨量計が十分でない山地域や利用できる雨量計がない海上では精度の向上は期待できないという欠点がある。一方、偏波レーダから得られる反射因子ZH と反射因子差ZDRを用いる降雨強度や雨水量の推定方法は、理論的には精度の良い推定方法であるが、波長の短い偏波レーダでは、反射因子ZH と反射因子差ZDRは降雨による減衰の影響を受けるために、豪雨時の降雨強度や雨水量の推定には大きな誤差を伴う。また、従来の推定式では温度や観測仰角の影響を考慮していないために、降雨強度や雨水量の3次元分布を求める際には誤差を生じる。 The estimation method of the rainfall intensity and the amount of rainwater using the conventional radar is not good in estimating the rain intensity due to various error factors such as radar calibration error, rain attenuation, and fluctuation of raindrop particle size distribution. Therefore, the Japan Meteorological Agency and others are trying to improve the accuracy by correcting the estimated value with the data of the rain gauge installed on the ground, but it is accurate in mountain areas where there are not enough rain gauges available or at sea where there are no rain gauges available. There is a disadvantage that improvement cannot be expected. On the other hand, the estimation method of the rainfall intensity and the amount of rain water using the reflection factor Z H and the reflection factor difference Z DR obtained from the polarization radar is theoretically a highly accurate estimation method. Since the reflection factor Z H and the reflection factor difference Z DR are affected by attenuation due to rain, there is a large error in estimating the rainfall intensity and the amount of rain water during heavy rain. In addition, since the conventional estimation formula does not consider the influence of temperature and observation elevation angle, an error occurs when obtaining the three-dimensional distribution of rainfall intensity and rainwater volume.
本発明は、上記課題を解決するものであって、降雨強度及び雨水量の3次元分布を精度良く推定できるようにするものである。 The present invention solves the above-described problems, and makes it possible to accurately estimate the three-dimensional distribution of rainfall intensity and amount of rainwater.
そのために本発明は、マルチパラメータレーダにより得られる比偏波間位相差KDP、反射因子差ZDR、反射因子ZH に基づき降雨強度と雨水量の3次元分布を推定する降雨強度と雨水量の3次元分布推定方法として、 For this purpose, the present invention estimates the three-dimensional distribution of rainfall intensity and rainfall based on the phase difference K DP , the reflection factor difference Z DR , and the reflection factor Z H obtained by the multi-parameter radar. As a 3D distribution estimation method,
のいずれかを降雨強度の推定式とし、 Either of the above is used as an estimation formula for rainfall intensity,
のいずれかを雨水量の推定式とし、
地上の気温t0 、レーダのレンジr、観測仰角θ、標準大気の気温減率Γ(=0.065℃/m)よりレンジ方向の温度プロファイルt(r,θ)
Is one of the formulas for estimating the amount of rainwater,
Temperature profile t (r, θ) in the range direction from the ground temperature t 0 , radar range r, observation elevation angle θ, and standard atmospheric temperature decrease rate Γ (= 0.065 ° C./m)
を計算し、温度依存性と仰角依存性を考慮した前記各推定式の係数とべき指数ai (i=1,2)、ai'(i=1,2)、bi (i=1,2)、bi'(i=1,2)、ci (i=1,2,3)、ci'(i=1,2,3)、di (i=1,2,3)、di'(i=1,2,3)を用い、
計算モードの選択を基に減衰補正の有無を判定して降雨減衰の補正を行い、計算方式の選択を基に前記〔数1〕のいずれの推定式かを判定して降雨強度を計算し、前記〔数2〕のいずれの推定式かを判定して雨水量を計算して、降雨強度と雨水量の3次元分布を推定することを特徴とする。
, And the coefficients and power exponents a i (i = 1, 2), a i ′ (i = 1, 2), b i (i = 1) of the above estimation equations in consideration of temperature dependency and elevation angle dependency 2), b i ′ (i = 1, 2), c i (i = 1, 2, 3), c i ′ (i = 1, 2, 3), d i (i = 1, 2, 3) ), D i ′ (i = 1, 2, 3) ,
Based on the selection of the calculation mode, the presence or absence of attenuation correction is determined to correct the rain attenuation. Based on the selection of the calculation method, the estimation formula of [Formula 1] is determined to calculate the rainfall intensity. It is characterized in that the estimation formula of [Equation 2] is determined and the amount of rainwater is calculated to estimate the three-dimensional distribution of the rainfall intensity and the amount of rainwater.
マルチパラメータレーダにより得られる比偏波間位相差KDP、反射因子差ZDR、反射因子ZH に基づき降雨強度と雨水量の3次元分布を推定する降雨強度と雨水量の3次元分布推定装置として、
計算モード及び計算方法を選択する選択手段と、
降雨減衰の影響を受けない偏波間位相差φDPの情報を利用した、自己無撞着法による降雨減衰の補正を行う補正手段と、
地上の気温t0 、レーダのレンジr、観測仰角θ、標準大気の気温減率Γ(=0.065℃/m)よりレンジ方向の温度プロファイルt(r,θ)
As a three-dimensional distribution estimator for rainfall intensity and rainfall, which estimates the three-dimensional distribution of rainfall intensity and rainfall based on phase difference K DP , reflection factor difference Z DR and reflection factor Z H obtained by multi-parameter radar ,
A selection means for selecting a calculation mode and a calculation method;
Correction means for correcting the rain attenuation by the self-consistent method using the information on the polarization phase difference φ DP that is not affected by the rain attenuation,
Temperature profile t (r, θ) in the range direction from the ground temperature t 0 , radar range r, observation elevation angle θ, and standard atmospheric temperature decrease rate Γ (= 0.065 ° C./m)
を計算する気温のレンジ方向のプロファイル計算手段と、
前記比偏波間位相差KDP、反射因子差ZDR、反射因子ZH 、仰角θ、レンジ方向の温度プロファイルt(r,θ)を入力し、前記選択手段により選択された計算モードを基に前記補正手段による降雨減衰の補正を行い、選択された計算方法を基に
A temperature range profile calculation means for calculating
The specific polarization phase difference K DP , the reflection factor difference Z DR , the reflection factor Z H , the elevation angle θ, and the temperature profile t (r, θ) in the range direction are input and based on the calculation mode selected by the selection means. The rain attenuation is corrected by the correction means and based on the selected calculation method.
のいずれかを降雨強度の推定式とし、 Either of the above is used as an estimation formula for rainfall intensity,
のいずれかを雨水量の推定式とし、
前記降雨強度と雨水量の3次元分布を推定する推定手段と
を備え、前記推定手段は、温度依存性と仰角依存性を考慮した前記各推定式の係数とべき指数ai (i=1,2)、ai'(i=1,2)、bi (i=1,2)、bi'(i=1,2)、ci (i=1,2,3)、ci'(i=1,2,3)、di (i=1,2,3)、di'(i=1,2,3)を用いることを特徴とする。
Is one of the formulas for estimating the amount of rainwater,
Estimation means for estimating a three-dimensional distribution of the rainfall intensity and the amount of rainwater, and the estimation means includes a coefficient and a power index a i (i = 1, 1) of each estimation formula taking temperature dependency and elevation angle dependency into consideration. 2), a i ′ (i = 1, 2), b i (i = 1, 2), b i ′ (i = 1, 2), c i (i = 1, 2, 3), c i ′ (I = 1, 2, 3), d i (i = 1, 2, 3), d i ′ (i = 1, 2, 3) are used.
また、前記推定手段は、前記計算モードが減衰補正無しであることを条件に前記R(KDP)、M(KDP)の計算を行うKDP法か、R(ZH )又はR(KDP)、M(ZH )又はM(KDP)の計算を行うコンポジット法Aのいずれかを選択し、前記計算モードが減衰補正有りであることを条件に前記R(ZH )又はR(KDP)、M(ZH )又はM(KDP)の計算を行うコンポジット法B、R(KDP,ZDR)、M(KDP,ZDR)の計算を行う(KDP,ZDR)法、R(ZH ,ZDR)、M(ZH ,ZDR)を計算する(ZH ,ZDR)法のいずれかを選択することを特徴とする。 In addition, the estimation means may use the K DP method for calculating the R (K DP ) and M (K DP ) on the condition that the calculation mode is no attenuation correction, R (Z H ) or R (K DP ), M (Z H ) or M (K DP ) is selected from the composite method A, and R (Z H ) or R ( K DP), M (Z H ) or M (K DP) composite method B perform computations, R (K DP, Z DR ), M (K DP, the calculation of Z DR) (K DP, Z DR ) method, R (Z H, Z DR ), M (Z H, calculates the Z DR) (Z H, and selects one of Z DR) method.
本発明によれば、3cm波長のマルチパラメータレーダを用い、観測仰角と温度変化を考慮した降雨強度推定式、雨水量推定式により降雨強度及び雨水量の3次元分布を推定するので、推定精度を大きく向上させることができる。 According to the present invention, a 3 cm wavelength multi-parameter radar is used to estimate the three-dimensional distribution of the rainfall intensity and the amount of rainwater based on the rainfall intensity estimation formula taking into account the observation elevation angle and temperature change, and the rainwater quantity estimation formula. It can be greatly improved.
以下、本発明の実施形態を図面を参照しつつ説明する。図1は本発明に係る降雨強度と雨水量の3次元分布推定装置の実施形態を説明する図、図2は降雨強度と雨水量の推定方法を説明するフローチャートである。 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of a three-dimensional distribution estimation apparatus for rainfall intensity and rainwater according to the present invention, and FIG. 2 is a flowchart for explaining a method for estimating rainfall intensity and rainwater.
図1において、1はマルチパラメータレーダシステム、2は測定データ、3は降雨強度と雨水量の3次元分布測定システム、4は推定部、5は減衰補正部、6は降雨強度と雨水量の3次元分布データ格納部、7は入力パラメータ処理部、8は気温のレンジ方向のプロファイル演算部、9は推定演算部を示す。マルチパラメータレーダシステム1は、波長3cmのマルチパラメータレーダシステムを利用し、水平偏波と垂直偏波の2種類の電波を利用したものである。雨の中を電波が伝わる時、僅かながら水平偏波は垂直偏波に比べて位相速度が遅くなる。これを偏波間位相差と呼び、本実施形態は、この偏波間位相差情報を利用するものである。偏波間位相差情報を利用した方法では在来型レーダの欠点、すなわち、レーダのキャリブレーション誤差、降雨減衰、雨滴粒径分布の変動といった様々な誤差要因の影響を受けにくいために、精度の良い雨の情報を推定することができる。測定データ2は、マルチパラメータレーダシステム1から出力される比偏波間位相差KDP、反射因子差ZDR、反射因子ZH 、観測仰角(アンテナ高度角)θなどのパラメータであり、降雨強度と雨水量の3次元分布の推定をおこなうものである。降雨強度と雨水量の3次元分布推定システム3は、推定部4、減衰補正部5、降雨強度と雨水量の3次元分布データ格納部6からなり、推定部4は、入力パラメータ処理部7、気温のレンジ方向のプロファイル演算部8、推定演算部9からなる。 In FIG. 1, 1 is a multi-parameter radar system, 2 is measurement data, 3 is a three-dimensional distribution measurement system for rainfall intensity and rainfall, 4 is an estimation unit, 5 is an attenuation correction unit, and 6 is 3 of rainfall intensity and rainfall. A dimension distribution data storage unit, 7 is an input parameter processing unit, 8 is a profile calculation unit in the temperature range direction, and 9 is an estimation calculation unit. The multi-parameter radar system 1 uses a multi-parameter radar system with a wavelength of 3 cm and uses two types of radio waves, horizontal polarization and vertical polarization. When radio waves are transmitted in the rain, the phase velocity of horizontal polarization is slightly slower than that of vertical polarization. This is called an inter-polarization phase difference, and this embodiment uses this inter-polarization phase difference information. The method using the phase difference information between polarizations is highly accurate because it is not easily affected by various error factors such as the disadvantages of conventional radar, that is, radar calibration error, rain attenuation, and raindrop size distribution fluctuation. Rain information can be estimated. The measurement data 2 includes parameters such as the specific polarization phase difference K DP , the reflection factor difference Z DR , the reflection factor Z H , the observation elevation angle (antenna altitude angle) θ, and the like, which are output from the multi-parameter radar system 1. It estimates the three-dimensional distribution of rainwater. The rainfall intensity and rainwater volume three-dimensional distribution estimation system 3 includes an estimation unit 4, an attenuation correction unit 5, and a rainfall intensity and rainwater volume three-dimensional distribution data storage unit 6. The estimation unit 4 includes an input parameter processing unit 7, It consists of a profile calculation unit 8 and an estimation calculation unit 9 in the temperature range direction.
次に、降雨強度と雨水量の3次元分布推定システム3による高強度と雨水量の3次元分布の推定方法について説明する。図2に示すようにまず、計算モード(減衰補正の有無)及び計算方法(KDP法、コンポジット法A、コンポジットB、(KDP,ZDR)法、(ZDR,ZH )法)の選択入力を行い(ステップS1)、マルチパラメータレーダシステムから観測データとして比偏波間位相差KDP、反射因子差ZDR、反射因子ZH 、仰角θを入力し(ステップS2)、さらに地上付近の温度t0 を入力して(ステップ3)、レンジ方向の温度プロファイルを計算し(ステップ4)、各地点の各高さ別温度を求める。次に、計算モードが減衰補正無しか、減衰補正有りかの判定を行う(ステップ5)。ステップ5による判定が減衰補正無しの場合には、計算方法がKDP法か、コンポジット法Aかの判定を行い(ステップS6)、その判定に基づきKDP法か、コンポジット法Aによる降雨強度と雨水量の3次元分布の計算を行う。KDP法又はコンポジット法Aは、リアルタイム性が要求されより速い計算が必要な場合に選択される。また、ステップS5による判定が減衰補正有りの場合には、降雨減衰の補正処理を行った後(ステップ7)、更に計算方法がコンポジット法Bか、(KDP,ZDR)法か、(ZDR,ZH )法かの判定を行い(ステップS8)、その判定に基づきコンポジット法B、(KDP,ZDR)法、又は(ZDR,ZH )法かによる降雨強度と雨水量の3次元分布の計算を行う。 Next, a method for estimating the three-dimensional distribution of the high intensity and the rainwater amount by the three-dimensional distribution estimation system 3 for the rainfall intensity and the rainwater amount will be described. As shown in FIG. 2, first, the calculation mode (with or without attenuation correction) and calculation method (K DP method, composite method A, composite B, (K DP , Z DR ) method, (Z DR , Z H ) method) Selective input is performed (step S1), and specific polarization phase difference K DP , reflection factor difference Z DR , reflection factor Z H , and elevation angle θ are input as observation data from the multi-parameter radar system (step S2). The temperature t 0 is input (step 3), the temperature profile in the range direction is calculated (step 4), and the temperature-dependent temperature at each point is obtained. Next, it is determined whether the calculation mode has no attenuation correction or has attenuation correction (step 5). When the decision in step 5 is no attenuation correction, the calculation method or K DP method performs Kano determination Composite Method A (step S6), and if K DP method based on the determination, and rain by the composite method A Calculate the three-dimensional distribution of rainwater. The KDP method or the composite method A is selected when real-time performance is required and faster calculation is required. If the determination in step S5 is attenuation correction, after performing rain attenuation correction processing (step 7), whether the calculation method is the composite method B, the (K DP , Z DR ) method, or (Z DR , Z H ) method is determined (step S8), and based on the determination, the rainfall intensity and the amount of rainwater by composite method B, (K DP , Z DR ) method or (Z DR , Z H ) method are determined. Calculate the three-dimensional distribution.
本実施形態では、降雨強度の推定式として、 In this embodiment, as an estimation formula of rainfall intensity,
のいずれかの計算を行い、雨水量の推定式とし、 To calculate the rainwater amount,
のいずれかの計算を行う。上記推定式の係数とべき指数ai (i=1,2)、ai'(i=1,2)、bi (i=1,2)、bi'(i=1,2)、ci (i=1,2,3)、ci'(i=1,2,3)、di (i=1,2,3)、di'(i=1,2,3)は、温度依存性と仰角依存性を考慮したものである。 Do one of the calculations. The coefficients and power exponents a i (i = 1, 2), a i ′ (i = 1, 2), b i (i = 1, 2), b i ′ (i = 1, 2), c i (i = 1, 2, 3), c i ′ (i = 1, 2, 3), d i (i = 1, 2, 3), d i ′ (i = 1, 2, 3) are Considering temperature dependency and elevation angle dependency.
係数とべき指数ai (i=1,2)、ai'(i=1,2)、bi (i=1,2)、bi'(i=1,2)、ci (i=1,2,3)、ci'(i=1,2,3)、di (i=1,2,3)、di'(i=1,2,3)は雨滴粒径分布測定装置により実測された雨滴粒径分布データに基づく散乱計算により求めることができる。散乱の計算には、T−マトリックス法が用いられ、散乱の計算条件として、例えば温度は3種類(0、15、30℃)、アンテナ高度角は5種類(0、10、20、30、40°)が用いられる。因みに、従来の偏波レーダによる降雨強度と雨水量の推定式では、係数の仰角や温度の変化について考慮されていない。本実施形態のように、温度依存性と仰角依存性を考慮することにより降水強度、雨水量の3次元分布を精度良く求めることができる。さらに、それぞれの計算内容について詳述する。 Coefficients and exponents a i (i = 1, 2), a i ′ (i = 1, 2), b i (i = 1, 2), b i ′ (i = 1, 2), c i (i = 1, 2, 3), c i ′ (i = 1, 2, 3), d i (i = 1, 2, 3), d i ′ (i = 1, 2, 3) are raindrop particle size distributions. It can be obtained by scattering calculation based on raindrop particle size distribution data actually measured by a measuring device. For the calculation of scattering, the T-matrix method is used. As the calculation conditions of scattering, for example, there are three types of temperature (0, 15, 30 ° C.) and five types of antenna altitude angles (0, 10, 20, 30, 40). °) is used. By the way, in the estimation formula of the rainfall intensity and the amount of rain water by the conventional polarization radar, the elevation angle of the coefficient and the change of the temperature are not taken into consideration. As in this embodiment, the three-dimensional distribution of precipitation intensity and amount of rainwater can be obtained with high accuracy by taking temperature dependency and elevation angle dependency into consideration. Furthermore, each calculation content is explained in full detail.
図3はレンジ方向の温度プロファイルの計算を説明する図である。標準大気を仮定すれば、気温の鉛直プロファイルは FIG. 3 is a diagram for explaining the calculation of the temperature profile in the range direction. Assuming standard atmosphere, the vertical profile of temperature is
の計算を行って求めることができる。ここで、Γは標準大気の気温減率(0.065℃/m)、zは地上からの高さである。 It can be obtained by calculating Here, Γ is the temperature reduction rate of the standard atmosphere (0.065 ° C./m), and z is the height from the ground.
一方、z=r sinθであるので、レンジ方向の温度プロファイルの計算は、レーダのレンジr、観測仰角θ、地上付近の温度t0 を入力して On the other hand, since z = r sin θ, the temperature profile in the range direction is calculated by inputting the radar range r, the observation elevation angle θ, and the temperature t 0 near the ground.
の計算を行って求めることができる。 It can be obtained by calculating
図4はKDP法を説明するフローチャートである。KDP法による降雨強度と雨水量の3次元分布の計算は、図4に示すようにまず、温度tからパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)の計算をおこなってから(ステップS11)、これらのパラメータとアンテナ仰角θから係数とべき指数bi (i=1,2),bi'(i=1,2)の計算を行い(ステップ12)、各パラメータと温度t、仰角θに基づき降雨強度R(KDP)と雨水量M(KDP)の計算を行う(ステップS13)。このKDP法は、レーダから測定されるKDP法を用いるので、最も速く計算を行うことができ、リアルタイム性が要求される場合には有効な手段である。ただし、弱い雨の場合の推定精度は悪くなるので、目安として8mm/h以下の降雨強度の場合には注意が必要である。 FIG. 4 is a flowchart for explaining the KDP method. As shown in FIG. 4, the calculation of the three-dimensional distribution of rainfall intensity and amount of rainwater by the K DP method starts with parameters α i (i = 0, 1, 2, 3), β i (i = 0, 1) After calculating α i ′ (i = 0, 1, 2, 3) and β i ′ (i = 0, 1) (step S11), the coefficient should be determined from these parameters and the antenna elevation angle θ. index b i (i = 1,2), b i ' perform calculations of (i = 1, 2) (step 12), the parameters and the temperature t, rainfall intensity based on the elevation angle θ R (K DP) and rainwater amount M (K DP ) is calculated (step S13). The K DP method, since using the K DP method is measured from the radar, it is possible to perform the fastest calculation, is an effective means in the case which requires real time. However, since the estimation accuracy in the case of light rain deteriorates, caution is required when the rainfall intensity is 8 mm / h or less as a guide.
の計算を行うKDP法において、係数とべき指数bi (i=1,2)、bi'(i=1,2)は、観測アンテナ仰角θと温度tに依存するので、bi (i=1,2)、bi'(i=1,2)として、 In the K DP method for performing calculations, coefficients and exponents b i (i = 1,2), b i '(i = 1,2) is dependent on the observation antenna elevation θ and the temperature t, b i ( i = 1, 2), b i ′ (i = 1, 2),
の多項式を仮定する。ここで、パラメータαi 、αi ´(i=0,1,2,3)、βi 、βi ´(i=0,1)は、温度tの2次関数で表されると仮定し、雨滴粒径分布データに基づく散乱シミュレーション結果に準ニュートン法(逐次2次計画法)を適用することにより求められる。 Is assumed to be a polynomial. Here, it is assumed that the parameters α i , α i ′ (i = 0, 1, 2, 3), β i , β i ′ (i = 0, 1) are expressed by a quadratic function of the temperature t. The quasi-Newton method (sequential quadratic programming method) is applied to the scattering simulation result based on the raindrop size distribution data.
上記述式[数5]と[数6]より任意の仰角θ、温度tの時の降雨強度と雨水量が計算される。 From the above formulas [Equation 5] and [Equation 6], the rainfall intensity and the amount of rainwater at an arbitrary elevation angle θ and temperature t are calculated.
図5はコンポジット法Aを説明するフローチャートである。コンポジット法Aによる降雨強度と雨水量の3次元分布の計算は、図5に示すようにまず、観測されたKDPの値がKDP_thrよりも大きいかどうかによって、R(ZH )とR(KDP)のどちらの推定式を用いるかの選択を行う(ステップS21)。KDPの値がKDP_thrよりも小さい時には、温度tから推定式R(ZH )についてのパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS22)、これらのパラメータとアンテナ仰角θから係数とべき指数ai (i=1,2)、ai'(i=1,2)を求め(ステップS23)、[数1]の中の推定式R(ZH )を用いて降雨強度の計算を行う。また、[数2]の中の推定式M(ZH )を用いて雨水量の計算を行う(ステップS24)。KDPの値がKDP_thrよりも大きい時には、温度tから推定式R(KDP)についてのパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS25)、これらのパラメータとアンテナ仰角θから係数とべき指数ai (i=1,2)、ai'(i=1,2)を求め(ステップS26)、[数1]の中の推定式R(KDP)を用いて降雨強度を、[数2]の中の推定式M(KDP)を用いて雨水量の計算を行う(ステップS27)。コンポジット法Aは弱い雨に対しては古典的な推定式R(ZH )とM(ZH )を用いることにより前述したKDP法の弱点、すなわち、KDP法は弱い雨に対して推定精度が低下するという点を改善するものである。ただし、ここで用いる反射因子ZH は降雨減衰の補正をおこなっていない。これはリアルタイムでの処理を行うためである。 FIG. 5 is a flowchart for explaining the composite method A. As shown in FIG. 5, the calculation of the three-dimensional distribution of the rainfall intensity and the amount of rainwater by the composite method A starts with R (Z H ) and R depending on whether the observed K DP value is larger than K DP _thr. Which estimation formula (K DP ) is used is selected (step S21). When the value of K DP is smaller than K DP _thr the parameters for estimation formula R (Z H) from the temperature t α i (i = 0,1,2,3) , β i (i = 0,1), α i ′ (i = 0, 1, 2, 3) and β i ′ (i = 0, 1) are obtained (step S22), and a coefficient and an exponent a i (i = 1) are calculated from these parameters and the antenna elevation angle θ. , 2), a i ′ (i = 1, 2) is obtained (step S23), and the rainfall intensity is calculated using the estimation formula R (Z H ) in [Equation 1]. Further, the amount of rainwater is calculated using the estimation formula M (Z H ) in [Equation 2] (step S24). When the value of K DP is greater than K DP _thr the parameters for estimation formula R (K DP) from the temperature t α i (i = 0,1,2,3) , β i (i = 0,1), α i ′ (i = 0, 1, 2, 3), β i ′ (i = 0, 1) are obtained (step S25), and the coefficient and power exponent a i (i = 1) are determined from these parameters and the antenna elevation angle θ. , 2), a i ′ (i = 1, 2) are obtained (step S26), and the rainfall intensity is estimated using the estimation formula R (K DP ) in [Equation 1] in [Equation 2]. The amount of rainwater is calculated using the equation M (K DP ) (step S27). The composite method A uses the classical estimation formulas R (Z H ) and M (Z H ) for light rain, and the weak point of the K DP method described above, that is, the K DP method estimates for light rain. This is to improve the point that accuracy decreases. However, the reflection factor Z H used here is not corrected for rain attenuation. This is because processing is performed in real time.
降雨減衰の補正をおこなうと、より精度の良い降雨強度と雨水量の推定が可能となる。偏波レーダでは降雨減衰の影響を受けない偏波間位相差φDPの情報を利用して、ZHHとZDRの降雨減衰を補正することができる。図2のフローチャートの中の降雨減衰補正(ステップS7)において採用している偏波パラメータの降雨減衰の補正方法は自己無撞着法によるもので、Bringi et al. (2001)がCバンドの偏波レーダに用いたものをXバンド用に改良したものである。自己無撞着法では「レンジr1 からr0 までの減衰係数AHHの積算値は同区間の偏波間位相差ΔφDP=φDP(r0 )−φDP(r1 )に一致する」という束縛条件を用いて最適な値が求められる。さらに「降雨エコーの遠方端(r0 )でのZDRはZH の一次関数で表される」という束縛条件を用いて最適な値が求められる(参考文献1:Bringi, V.N, T. D. Keenan, and V. Chandrasekar, 2001: Correcting C-band radar reflectivity and differential reflectivity data for rain attenuation: A self-consistent method with constraints. IEEE Trans. Geosci. Remote Sens., 39, 1906-1915.)。 If the rain attenuation is corrected, it is possible to estimate the rain intensity and the amount of rain water with higher accuracy. Polarization radar can correct the rain attenuation of Z HH and Z DR by using the information of the phase difference φ DP between the polarization waves that is not affected by the rain attenuation. In the flowchart of FIG. 2, the rain attenuation correction method of the polarization parameter used in the rain attenuation correction (step S7) is a self-consistent method. Bringi et al. (2001) The one used for the radar is improved for the X band. In the self-consistent method, “the integrated value of the attenuation coefficient A HH from the range r 1 to r 0 agrees with the polarization phase difference Δφ DP = φ DP (r 0 ) −φ DP (r 1 ) in the same section”. The optimum value is obtained using the binding condition. Furthermore, an optimum value is obtained using the constraint that “Z DR at the far end (r 0 ) of the rain echo is expressed by a linear function of Z H ” (Reference 1: Bringi, VN, TD Keenan, and V. Chandrasekar, 2001: Correcting C-band radar reflectivity and differential reflectivity data for rain attenuation: A self-consistent method with constraints. IEEE Trans. Geosci. Remote Sens., 39, 1906-1915.).
図6はコンポジット法Bを説明するフローチャートである。コンポジット法Bによる降雨強度と雨水量の3次元分布の計算は、コンポジット法Aと似ているが、推定式の選択条件が異なる。さらに、コンポジット法Aでは降雨減衰補正なしの反射因子ZH を用いるのに対して、コンポジット法Bでは降雨減衰補正されたZH _corを用いる点が異なる。図6に示すように、まず、観測されたKDPの値がKDP_thrよりも大きいかどうか、減衰補正されたZH _corの値がZH _thrよりも大きいかどうかによって、R(ZH )とR(KDP)のどちらの推定式を用いるかの選択を行う(ステップS31)。KDPの値がKDP_thr以下の時またはZH _corの値がZH _thr以下の時には、温度tから推定式R(Z)についてのパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS32)、これらのパラメータとアンテナ仰角θから係数とべき指数ai (i=1,2)、ai'(i=1,2)を求め(ステップS33)、[数1]の推定式R(ZH )を用いて降雨強度の計算を行い、[数2]の推定式M(ZH )を用いて雨水量の計算を行う(ステップS34)。KDPの値がKDP_thr よりも大きい時でかつZH _cor の値がZH _thr よりも大きい時には、温度tから推定式R(KDP)についてのパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS35)、これらのパラメータとアンテナ仰角θから係数とべき指数ai (i=1,2)、ai'(i=1,2)を求め(ステップS36)、[数1]の推定式R(KDP)を用いて降雨強度を、[数2]の推定式M(KDP)を用いて雨水量の計算を行う。 FIG. 6 is a flowchart for explaining the composite method B. Calculation of the three-dimensional distribution of the rainfall intensity and the amount of rainwater by the composite method B is similar to the composite method A, but the selection conditions for the estimation formula are different. Further, the composite method A uses a reflection factor Z H without rain attenuation correction, whereas the composite method B uses Z H — cor corrected for rain attenuation. As shown in FIG. 6, first, R (Z H depends on whether the observed K DP value is larger than K DP — thr and whether the attenuation corrected Z H — cor value is larger than Z H — thr. ) Or R (K DP ) to be used is selected (step S31). K DP of when the value is the value of time or Z H _cor follows K DP _thr is below Z H _thr the parameters for estimation formula R (Z) from the temperature t α i (i = 0,1,2,3) , Β i (i = 0, 1), α i ′ (i = 0, 1, 2, 3), β i ′ (i = 0, 1) are obtained (step S32), and these parameters and the antenna elevation angle θ From the coefficients and power exponents a i (i = 1, 2) and a i ′ (i = 1, 2) (step S33), and using the estimation formula R (Z H ) of [Equation 1] The calculation is performed, and the amount of rainwater is calculated using the estimation formula M (Z H ) of [Equation 2] (step S34). K When greater than when a and Z H value of _cor is Z H _ thr value is greater than K DP _ thr the DP, the parameter α i (i = 0 for estimation formula R (K DP) from the temperature t, 1, 2, 3), β i (i = 0, 1), α i ′ (i = 0, 1, 2, 3), β i ′ (i = 0, 1) are obtained (step S35). And the exponents a i (i = 1, 2) and a i ′ (i = 1, 2) are obtained from the parameters of the antenna and the antenna elevation angle θ (step S36), and the estimation formula R (K DP ) of [Equation 1] Is used to calculate the rainfall intensity, and the rainwater quantity is calculated using the estimation formula M (K DP ) of [Equation 2].
図7は(KDP,ZDR)法を説明するフローチャートである。(KDP,ZDR)法による降雨強度と雨水量の3次元分布の計算は、図5に示すようにまず、温度tからパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS41)、これらのパラメータとアンテナ仰角θから係数とべき指数ci (i=1,2)、ci'(i=1,2)を求め(ステップS42)、〔数1〕の推定式R(KDP,ZDR)を用いて降雨強度の計算を行い、〔数2〕の推定式M(KDP,ZDR)を用いて雨水量の計算を行う(ステップS43)。なお、ここで用いるZDRは降雨減衰補正後のものである。KDP_thr =0.3°/kmを仮定するが、状況によってはもう少し大きい値を用いても良い。KDP_thr =0.3°/kmは仰角0°で温度15 ℃の場合、降雨強度に換算すると7.3mm/hである。 FIG. 7 is a flowchart for explaining the (K DP , Z DR ) method. As shown in FIG. 5, the calculation of the three-dimensional distribution of the rainfall intensity and the amount of rainwater by the (K DP , Z DR ) method starts with the parameters α i (i = 0, 1, 2, 3), β i from the temperature t. (I = 0, 1), α i ′ (i = 0, 1, 2, 3), β i ′ (i = 0, 1) are obtained (step S41), and a coefficient is calculated from these parameters and the antenna elevation angle θ. The power exponents c i (i = 1, 2) and c i ′ (i = 1, 2) are obtained (step S42), and the rainfall intensity is calculated using the estimation formula R (K DP , Z DR ) of [Equation 1]. Calculation is performed, and the amount of rainwater is calculated using the estimation formula M (K DP , Z DR ) of [Equation 2] (step S43). The Z DR used here is after rain attenuation correction. Although K DP — thr = 0.3 ° / km is assumed, a slightly larger value may be used depending on the situation. K DP — thr = 0.3 ° / km is 7.3 mm / h in terms of rainfall intensity when the elevation angle is 0 ° and the temperature is 15 ° C.
図8は(ZH ,ZDR)法を説明するフローチャートである。(ZH ,ZDR)法による降雨強度と雨水量の3次元分布の計算は、図8に示すようにまず、温度tからパラメータαi (i=0,1,2,3)、βi (i=0,1)、αi ´(i=0,1,2,3)、βi ´(i=0,1)を求め(ステップS41)、これらのパラメータとアンテナ仰角θから係数とべき指数ci (i=1,2)、ci'(i=1,2)を求め(ステップS42)、〔数1〕の推定式R(ZH ,ZDR)を用いて降雨強度の計算を行い、〔数2〕の推定式M(MH _cor ,ZDR_cor )を用いて雨水量の計算を行う(ステップS43)。なお、ここで用いるZH とZDRはいずれも降雨減衰補正後のものである。 FIG. 8 is a flowchart for explaining the (Z H , Z DR ) method. As shown in FIG. 8, the calculation of the three-dimensional distribution of the rainfall intensity and the amount of rainwater by the (Z H , Z DR ) method starts with parameters α i (i = 0, 1, 2, 3), β i from the temperature t. (I = 0, 1), α i ′ (i = 0, 1, 2, 3), β i ′ (i = 0, 1) are obtained (step S41), and a coefficient is calculated from these parameters and the antenna elevation angle θ. The power indices c i (i = 1, 2) and c i ′ (i = 1, 2) are obtained (step S42), and the rainfall intensity is calculated using the estimation formula R (Z H , Z DR ) of [Equation 1]. Calculation is performed, and the amount of rainwater is calculated using the estimation formula M (M H — cor, Z DR — cor) of [Equation 2] (step S43). Note that Z H and Z DR used here are after rain attenuation correction.
〔数1〕の降雨強度推定式と係数とべき指数ai (i=1,2)、bi (i=1,2)、ci (i=1,2,3)、di (i=1,2,3)及び[ 数2] の雨水量推定式のai'(i=1,2)、bi'(i=1,2)、ci'(i=1,2,3)、di'(i=1,2,3)は文献などですでに提案されているが、それらの値は仰角や温度の変化については考慮されていない。従って、その値を用いて降雨強度や雨水量の3次元分布を求めた場合には誤差が生じる場合がある。 [Expression 1] Rain intensity estimation formula, coefficient and exponents a i (i = 1, 2), b i (i = 1, 2), c i (i = 1, 2, 3), d i (i = 1, 2, 3) and a rain water quantity estimation formula of [Equation 2] a i ′ (i = 1, 2), b i ′ (i = 1, 2), c i ′ (i = 1, 2, 3) and d i ′ (i = 1, 2, 3) have already been proposed in the literature, but their values do not take into account changes in elevation angle or temperature. Therefore, an error may occur when the three-dimensional distribution of the rainfall intensity and the amount of rainwater is obtained using the value.
本件で用いる方法は、これらの係数とべき指数の温度依存性と仰角依存性を考慮したもので、この点に進歩性がある。すなわち、本発明は降雨強度と雨水量の3次元分布の精度良い測定をおこなうために、〔数1〕と〔数2〕の降雨強度と雨水量の推定式の係数と指数が温度tと観測仰角θの関数であることを一つの特徴としている。以下、もし温度tや観測仰角θの影響を無視した場合にどの程度の誤差が生じるかについて詳述する。 The method used in this case takes into account the temperature dependence and elevation angle dependence of these coefficients and power exponents, and is inventive in this respect. That is, in order to accurately measure the three-dimensional distribution of the rainfall intensity and the amount of rainwater in the present invention, the coefficient and index of the estimation formula of the rain intensity and the rainwater amount of [Equation 1] and [Equation 2] are measured with the temperature t. One feature is that it is a function of the elevation angle θ. Hereinafter, it will be described in detail how much error occurs when the influence of the temperature t and the observation elevation angle θ is ignored.
まず、降水強度についての結果を述べる。θ=0°の係数とべき指数を他のθに用いた場合に生じる相対誤差をΔRθ/R0 とする。また、t0 =20℃の係数とべき指数を他の温度tに用いた場合に生じる相対誤差をΔRt /R0 とする。それぞれの推定式について求めた結果を以下に示す。 First, the results on precipitation intensity will be described. A relative error that occurs when a coefficient of θ = 0 ° and a power index are used for other θ is ΔRθ / R 0 . Further, a relative error that occurs when a coefficient of t 0 = 20 ° C. and a power index are used for another temperature t is represented by ΔR t / R 0 . The results obtained for each estimation formula are shown below.
(a)推定式R(ZH )の場合の仰角依存性と温度依存性についての結果を図9に示す。図9(A)からわかるように、仰角θを0°の係数とべき指数を他の仰角に用いたときに生じる相対誤差は仰角とともに大きくなるが、θ=60°でもその大きさは3%程度である。一方、図9(B)からわかるように、温度が20℃の場合の係数とべき指数を他の温度に用いたときに生じる相対誤算は温度が低くなると大きくなり、降雨強度が大きくなると大きくなる。例えばt=0℃では降雨強度R0 =160mm/hの場合には相対誤差は約−10%となる。 (A) The results of the elevation angle dependency and the temperature dependency in the case of the estimation formula R (Z H ) are shown in FIG. As can be seen from FIG. 9A, the relative error that occurs when the elevation angle θ is a coefficient of 0 ° and the exponent is used for other elevation angles increases with the elevation angle, but the magnitude is 3% even when θ = 60 °. Degree. On the other hand, as can be seen from FIG. 9B, the relative miscalculation that occurs when the coefficient and power index when the temperature is 20 ° C. is used for other temperatures increases as the temperature decreases, and increases as the rainfall intensity increases. . For example, at t = 0 ° C., when the rainfall intensity R 0 = 160 mm / h, the relative error is about −10%.
(b)推定式R(KDP)の場合の仰角依存性と温度依存性についての結果を図10に示す。図10(A)からわかるように、仰角0°の場合の係数を他の仰角に用いたときに生じる相対誤差の絶対値は仰角とともに大きくなりθ=20°では約10%の過少評価、θ=60°では約60%の過少評価をもたらす。θ=5°以下では相対誤差の絶対値は約1%以下であり、仰角依存性は無視できる。このような仰角依存性は係数b1 の仰角依存性によるものである。一方、図10(B)からわかるように、温度が20℃の場合の係数とべき指数を他の温度に用いたときに生じる相対誤算は±2%程度である。R0 が40mm/hよりも大きいときには過大評価を、40mm/hよりも小さいときには過小評価する。ΔRt /R0 は大きくても2%程度であり実用上、温度依存性は無視できる。 (B) FIG. 10 shows the results of the elevation angle dependency and the temperature dependency in the case of the estimation formula R (K DP ). As can be seen from FIG. 10A, the absolute value of the relative error generated when the coefficient at the elevation angle of 0 ° is used for other elevation angles increases with the elevation angle, and underestimation of about 10% at θ = 20 °, θ = 60 ° results in an underestimation of about 60%. When θ = 5 ° or less, the absolute value of the relative error is about 1% or less, and the elevation angle dependency can be ignored. Such elevation angle dependency is due to the elevation angle dependency of the coefficient b 1 . On the other hand, as can be seen from FIG. 10B, the relative miscalculation that occurs when the coefficient and power index when the temperature is 20 ° C. is used for other temperatures is about ± 2%. When R 0 is larger than 40 mm / h, overestimation is performed, and when R 0 is smaller than 40 mm / h, it is underestimated. ΔR t / R 0 is about 2% at most and practically the temperature dependence can be ignored.
(c)推定式R(KDP,ZDR)の場合の仰角依存性と温度依存性についての結果を図11に示す。図11(A)からわかるように、ΔRθ/R0 の絶対値は仰角とともに大きくなる。例えば、R0 が40mm/hの時、θ=20°では約7%の過少評価、θ=60°では約55%の過少評価をもたらす。このような相対誤差の仰角依存性は係数c1 とc3 の仰角依存性とZDRの大きさによるものである。一方、図11(B)からわかるように、温度が20℃の場合の係数とべき指数を他の温度に用いたときに生じる相対誤算は−1%から+3%程度である。結果はR(KDP)の場合と良く似ており、R0 が20mm/hよりも大きいときには過大評価を、20mm/hよりも小さいときには過小評価する。 (C) FIG. 11 shows the results of the elevation angle dependency and the temperature dependency in the case of the estimation formula R (K DP , Z DR ). As can be seen from FIG. 11A, the absolute value of ΔRθ / R 0 increases with the elevation angle. For example, when R 0 is 40 mm / h, about 7% underestimation occurs when θ = 20 °, and about 55% underestimation occurs when θ = 60 °. Such elevation angle dependency of the relative error is due to the elevation angle dependency of the coefficients c 1 and c 3 and the magnitude of Z DR . On the other hand, as can be seen from FIG. 11B, the relative miscalculation that occurs when the coefficient and power exponent when the temperature is 20 ° C. is used for other temperatures is about −1% to + 3%. The result is very similar to R (K DP ), overestimating when R 0 is greater than 20 mm / h and underestimating when less than 20 mm / h.
(d)推定式R(ZH ,ZDR)の場合の仰角依存性と温度依存性についての結果を図12に示す。図12(A)からわかるように、ΔRθ/R0 は仰角とともに大きくなる。例えば、R0 =40mm/h、θ=20°では約20%の過大評価、θ=60°では約160%の過大評価をもたらす。R0 =160mm/hの時には、θ=20°では約30%の過大評価、θ=60°では約250%の過大評価となる。このようなΔRθ/R0 の仰角依存性は係数d1 とべき指数d3 の仰角依存性によるものでZH の大きさにはよらない。一方、図12(B)からわかるように、温度が20℃の場合の係数を他の温度に用いたときに生じる相対誤算はθが30°まではR0 =10mm/h〜160mm/hの範囲で9%から3%で、過大評価される。θ=60°では若干大きくなり、R0 =10mm/h〜160mm/hの範囲で10%〜6%の過大評価をもたらす。過大評価の度合いは降雨強度R0 が大きくなると小さくなる。 (D) FIG. 12 shows the results of elevation angle dependency and temperature dependency in the case of the estimation formula R (Z H , Z DR ). As can be seen from FIG. 12A, ΔRθ / R 0 increases with the elevation angle. For example, when R 0 = 40 mm / h and θ = 20 °, an overestimation of about 20% is brought about, and when θ = 60 °, an overestimation of about 160% is brought about. When R 0 = 160 mm / h, overestimation of about 30% is obtained at θ = 20 °, and overestimation of about 250% is obtained at θ = 60 °. The elevation angle dependency of ΔRθ / R 0 is due to the elevation angle dependency of the coefficient d 1 and the power index d 3 and does not depend on the magnitude of Z H. On the other hand, as can be seen from FIG. 12B, the relative miscalculation that occurs when the coefficient when the temperature is 20 ° C. is used for other temperatures is that R 0 = 10 mm / h to 160 mm / h until θ is 30 °. It is overestimated in the range of 9% to 3%. It becomes slightly larger at θ = 60 °, resulting in an overestimation of 10% to 6% in the range of R 0 = 10 mm / h to 160 mm / h. The degree of overestimation decreases as the rainfall intensity R 0 increases.
以上示したようにな降雨強度推定式の係数とべき指数ai (i=1,2)、bi (i=1,2)、ci (i=1,2,3)、di (i=1,2,3)の仰角依存性と温度依存性は、雨水量の推定式の係数とべき指数ai'(i=1,2)、bi'(i=1,2)、ci'(i=1,2,3)、di'(i=1,2,3)についてもあることが散乱シミュレーションの結果から示すことができる(図は省略)。 Coefficients and power indices a i (i = 1, 2), b i (i = 1, 2), c i (i = 1, 2, 3), d i ( The elevation angle dependency and temperature dependency of i = 1, 2, 3) are the coefficient of the rainwater estimation equation and the power exponents a i ′ (i = 1, 2), b i ′ (i = 1, 2), It can be shown from the result of the scattering simulation that c i ′ (i = 1, 2, 3) and d i ′ (i = 1, 2, 3) are also present (not shown).
従って、降雨強度と雨水量の3次元分布の精度良い推定をおこなうためには、[数1]と[数2]の各推定式の係数およびべき指数は温度依存性と仰角依存性を考慮しなければならない。 Therefore, in order to accurately estimate the three-dimensional distribution of rainfall intensity and rainfall, the coefficients and power exponents of the estimation equations in [Equation 1] and [Equation 2] take temperature dependence and elevation angle dependence into consideration. There must be.
以下では、実際の降雨について本発明を適用した例を示す。図13は本発明を適用した3cm波長のマルチパラメータレーダの外観とシステム構成図である。このレーダは防災科学技術研究所が2000年に開発完成したマルチパラメータである。写真の白い球状のカバーはレドームでこの中にパラボラアンテナが入っており、各種機器はアンテナ架台の下のコンテナ内に収納されている。波長3cmであること、水平偏波と垂直偏波の二種類の電波を発射し、様々な偏波パラメータを測定することがこのレーダの特徴となっている。 Below, the example which applied this invention about actual rainfall is shown. FIG. 13 is an external view and system configuration diagram of a 3 cm wavelength multi-parameter radar to which the present invention is applied. This radar is a multi-parameter developed and completed in 2000 by the National Research Institute for Earth Science and Disaster Prevention. The white spherical cover in the photo is a radome with a parabolic antenna inside, and various devices are stored in a container under the antenna mount. A characteristic of this radar is that it has a wavelength of 3 cm, emits two types of radio waves of horizontal polarization and vertical polarization, and measures various polarization parameters.
図14は在来型レーダの測定原理と本発明に用いた3cm波長マルチパラメータレーダシステム装置の測定原理を示す図、図15は本発明に用いた3cm波長マルチパラメータレーダシステム装置により測定されるパラメータの例である。在来型レーダでは反射因子ZH が測定されるのに対して、マルチパラメータではZH に加えて、反射因子差ZDR、比偏波間位相差KDPが測定される。 FIG. 14 is a diagram showing the measurement principle of a conventional radar and the measurement principle of the 3 cm wavelength multi-parameter radar system apparatus used in the present invention. FIG. 15 is a parameter measured by the 3 cm wavelength multi-parameter radar system apparatus used in the present invention. It is an example. While the conventional radar measures the reflection factor Z H , the multi-parameter measures the reflection factor difference Z DR and the specific polarization phase difference K DP in addition to Z H.
図16は本発明により求められた降雨強度の3次元分布の例(2003年8月9日、台風10号)で、図17は本発明により求められた雨水量の3次元分布の例(2003年8月9日、台風10号)である。 FIG. 16 is an example of a three-dimensional distribution of rainfall intensity obtained by the present invention (Typhoon No. 10 on August 9, 2003), and FIG. 17 is an example of a three-dimensional distribution of rainwater obtained by the present invention (2003). August 9th, Typhoon No.10).
なお、本発明で例示した降雨強度と雨水量の各推定式の観測仰角依存性と温度依存性についての結果は3cm波長のマルチパラメータレーダに関するものであるが、他の波長のマルチパラメータレーダについても同様な議論が可能である。 Note that the results of the observation elevation angle dependency and temperature dependency of each estimation formula of the rainfall intensity and the amount of rain water exemplified in the present invention relate to the multi-parameter radar of 3 cm wavelength, but the multi-parameter radar of other wavelengths also applies. Similar discussions are possible.
1…マルチパラメータレーダシステム、2…測定データ、3…降雨強度と雨水量の3次元分布測定システム、4…推定部、5…減衰補正部、6…降雨強度と雨水量の3次元分布データ格納部、7…入力パラメータ処理部、8…気温のレンジ方向のプロファイル演算部、9…推定演算部 DESCRIPTION OF SYMBOLS 1 ... Multi-parameter radar system, 2 ... Measurement data, 3 ... Three-dimensional distribution measurement system of rainfall intensity and rain water quantity, 4 ... Estimation part, 5 ... Attenuation correction part, 6 ... Three-dimensional distribution data storage of rainfall intensity and rain water quantity Unit 7 input parameter processing unit 8 temperature profile calculation unit in temperature range direction 9 estimation calculation unit
Claims (4)
地上の気温t0 、レーダのレンジr、観測仰角θ、標準大気の気温減率Γ(=0.065℃/m)よりレンジ方向の温度プロファイルt(r,θ)
計算モードの選択を基に減衰補正の有無を判定して降雨減衰の補正を行い、計算方式の選択を基に前記〔数1〕のいずれの推定式かを判定して降雨強度を計算し、前記〔数2〕のいずれの推定式かを判定して雨水量を計算して、降雨強度と雨水量の3次元分布を推定することを特徴とする降雨強度と雨水量の3次元分布推定方法。 A method for estimating the three-dimensional distribution of rainfall intensity and rainfall based on the phase difference K DP , the reflection factor difference Z DR and the reflection factor Z H obtained by multi-parameter radar. There,
Temperature profile t (r, θ) in the range direction from the ground temperature t 0 , radar range r, observation elevation angle θ, and standard atmospheric temperature decrease rate Γ (= 0.065 ° C./m)
Based on the selection of the calculation mode, the presence or absence of attenuation correction is determined to correct the rain attenuation. Based on the selection of the calculation method, the estimation formula of [Formula 1] is determined to calculate the rainfall intensity. A method for estimating a three-dimensional distribution of rainfall intensity and rainwater amount, wherein the estimation formula of [Equation 2] is determined and a rainwater amount is calculated to estimate a three-dimensional distribution of rainfall intensity and rainwater amount .
計算モード及び計算方法を選択する選択手段と、
降雨減衰の補正を行う補正手段と、
地上の気温t0 、レーダのレンジr、観測仰角θ、標準大気の気温減率Γ(=0.065℃/m)よりレンジ方向の温度プロファイルt(r,θ)
前記比偏波間位相差KDP、反射因子差ZDR、反射因子ZH 、仰角θ、レンジ方向の温度プロファイルt(r,θ)を入力し、前記選択手段により選択された計算モードを基に前記補正手段による降雨減衰の補正を行い、選択された計算方法を基に
前記降雨強度と雨水量の3次元分布を推定する推定手段と
を備え、前記推定手段は、温度依存性と仰角依存性を考慮した前記各推定式の係数とべき指数ai (i=1,2)、ai'(i=1,2)、bi (i=1,2)、bi'(i=1,2)、ci (i=1,2,3)、ci'(i=1,2,3)、di (i=1,2,3)、di'(i=1,2,3)を用いることを特徴とする降雨強度と雨水量の3次元分布推定装置。 A three-dimensional distribution estimation device for rainfall intensity and rainfall, which estimates the three-dimensional distribution of rainfall intensity and rainfall based on the phase difference K DP , reflection factor difference Z DR and reflection factor Z H obtained by multi-parameter radar There,
A selection means for selecting a calculation mode and a calculation method;
Correction means for correcting rain attenuation;
Temperature profile t (r, θ) in the range direction from the ground temperature t 0 , radar range r, observation elevation angle θ, and standard atmospheric temperature decrease rate Γ (= 0.065 ° C./m)
The specific polarization phase difference K DP , the reflection factor difference Z DR , the reflection factor Z H , the elevation angle θ, and the temperature profile t (r, θ) in the range direction are input and based on the calculation mode selected by the selection means. The rain attenuation is corrected by the correction means and based on the selected calculation method.
Estimation means for estimating a three-dimensional distribution of the rainfall intensity and the amount of rainwater, and the estimation means includes a coefficient and a power index a i (i = 1, 1) of each estimation formula considering temperature dependence and elevation angle dependence. 2), a i ′ (i = 1, 2), b i (i = 1, 2), b i ′ (i = 1, 2), c i (i = 1, 2, 3), c i ′ (I = 1, 2, 3), d i (i = 1, 2, 3), d i ′ (i = 1, 2, 3) Estimating device.
の計算を行うコンポジット法Aのいずれかを選択することを特徴とする請求項2の記載の降雨強度と雨水量の3次元分布推定装置。 The estimation means may be a K DP method for calculating the R (K DP ) and M (K DP ) on condition that the calculation mode is no attenuation correction, or R (Z H ) or R (K DP ). , M (Z H ) or M (K DP )
3. The apparatus for estimating a three-dimensional distribution of rainfall intensity and amount of rain water according to claim 2, wherein any one of the composite methods A for performing the calculation is selected.
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