青藏高原地形复杂， 雷达波束遮挡严重， 零度层亮带及以上冰相过程对降水估测的影响显著， 至今为止尚没有适合于青藏高原的雷达估测降水方法。利用2008—2010年汛期青海西宁雷达和雨量站资料， 在对资料进行质量控制的基础上， 根据雨量计观测的总雨量与雷达估测总雨量相等的条件， 建立适合于青藏高原地区各类型降水的气候Z-R关系， 并利用雨量计对雷达估测的降水进行校准。结果表明, 新建立的适合青藏高原地区的气候Z-R关系可以减小常规经验Z-R关系对降水的严重低估； 在亮带区， 应先进行亮度层亮带的订正， 再用适合的Z-R关系(Z=29R1.6)估测降水； 对亮带区的高反射率因子进行亮带识别和订正， 并用各类型降水相应的Z-R关系估测降水， 可以减小雷达估测降水的误差， 提高雷达估测降水的精度； 平均校准法可以避免测站稀少和单个测站随机误差大而造成的校准不稳定， 进一步提高青藏高原测站稀少地区的降水估测精度。
There has been little research about radar-derived quantitative precipitation estimation over the Qinghai-XizangPlateau due to the complex terrain, severe radar beam blockage and few rain gauges until now. Radar and gauge data of thirteen storm events in Xining from 2008 to 2010 had been quality controlled to construct the new climatology Z-R relationshipsof different precipitation types which wereadjusted based on comparison of gauge and radar rainfall. The gauge mean calibration method is developed on the bases of the precipitation classification and bright band (BB) correction. The results show that the significant underestimations of precipitation are successfully reduced by the new constructed Z-R relationship of different precipitation types. As to the precipitation estimation on the BB areas, BB correction should be applied before precipitation estimation using the perfect (Z=29R1.6) Z-R relationship. The precipitation estimation error reduces due to the high reflectivity are corrected on BB areas and applying the perfect Z-R relationship of different precipitation types. The gauge mean calibration method can further improve the accuracy of precipitation estimation on the basis of BB correction and precipitation classification in the Qinghai-Xizang Plateau.
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