C頻偏振雷達總傳播相位偏移差面積雨量估計法之研究

The Rainfall Estimation Using Total Propagation Differential Phase Shift by C-band Polarimetric Radar

鳳雷(Lei Feng) ； 周仲島(Ben Jong-Dao Jou)

《大氣科學》 34卷2期 (2006/06) Pp. 89-100

摘要

本文使用澳洲氣象局研究中心(Bureau of Meteorology Research Centre, BMRC)與美國大氣研究中心(National Center for Atmospheric Research, NCAR)合作研發的雙線性偏振C頻氣象雷達(C-Pol)，對科羅拉多州立大學的面積雨量估計法Areal R(下標 CSU)(Φ(下標 DP))及美國國家劇烈風暴實驗室(National Severe Storms Laboratory, NSSL)的面積雨量估計法Areal R(下標 NSSL)(Φ(下標 DP))進行實際驗証，利用C-Pol雷達於1999年夏天在澳洲達爾文地區所觀測的三個降水個案及地面雨量計網資料評估兩種雷達雨量估計方法之準確度。面積雨量估計分成大面積(110km^2)及小面積(25km^2)兩種，地面降雨率分成3分鐘及10分鐘平均兩種。結果顯示，上述兩種Areal R(Φ(下標 DP))雷達雨量估計法之準確度相當接近，雷達估計之降雨率與地面雨量計網之3分鐘及10分鐘平均降雨率的相關性分析，大面積之相關係數大於0.95，小面積之相關係數大於0.91。分析中亦顯示，兩種面積雨量估計法在對流性降雨量的估計上均有很好的表現。

關鍵字

偏振雷達 ； 總傳播相位偏移差 ； 面積雨量估計法

並列摘要

in this paper, the BMRC/NCAR C-band polarimetric radar (C-Pol) was used to verify the performances of the Areal R(subscript CSU)(Φ(subscript DP)) (Bringi et al., 2001a) and Areal R(subscript NSSL)(Φ(subscript DP)) (Ryzhkov et al., 2000) on areal rainfall estimations. On the summer of 1999, three rainfall events at Darwin were observed by the C-Pol radar and the rainfalls were measured by a dense rain gauge network. The area of rainfall estimation has been divided into large area (~110km^2) and small area (~25km^2). 3 minutes and 10 minutes time intervals were used to average the rain rates of rain gauges. Although these two estimators have different hypothesis, the results showed that these two areal rainfall estimators were very similar. The correlation coefficients between the average rain rates of the rain gauges and radar estimated rain rates are quite high. Both of the correlation coefficients are greater than 0.95 in large area and 0.91 in small area. The results of this paper demonstrate that the Areal R(Φ(subscript DP)) rainfall estimators are useful tools for the convective rainfall estimation.

並列關鍵字

Polarimetric radar ； Total propagation differential phase shift ； Areal rainfall estimation