1960—2006年重庆高温日数时空变化特征

利用重庆市1960-2006年35个地面气象站逐日气温资料,分析了近47年来重庆市高温日数的时空变化特征.结果表明:重庆市有四个主要的高温多发区,分别在东北角的巫山、北部的万州、中部的涪陵和丰都一带以及西南角的万盛和綦江附近;较重高温、严重高温和特别严重高温的最大值分别为21d/a、14d/a和2d/a左右.重庆市高温日主要发生在7月和8月,其中8月的高温日数和高温强度都大于7月;近47年全市高温日数大体呈现出"增加-减少-增加"的变化趋势;尤其是大于40℃的高温日数变化最为明显.     

Validation of the Atmospheric Infrared Sounder Retrieval Products over China and Their Application in Numerical Model

The atmospheric infrared sounder (AIRS) instrument onboard Aqua Satellite is a high spectral resolution infrared sounder. In recent years, AIRS has gradually become the primary method of atmospheric vertical observations. To examine the validation of AIRS retrieval products (V3.0) over China, the AIRS surface air temperature retrievals were compared with the ground observations obtained from 540 meteorological stations in July 2004 and January 2005, respectively. The sources of errors were considerably discussed. Based on the error analysis, the AIRS retrieved surface air temperature products were systemi-cally corrected. Moreover, the AIRS temperature and humidity profile retrievals were compared with T213 numerical forecasting products. Because T213 forecasting products are not the actual atmospheric states, to further verify the validation, the AIRS temperature and humidity profile products were assimilated into the MM5 model through the analysis nudging. In this paper, the case on February 14, 2005 in North China was simulated in detail. Then, we investigated the effects of AIRS retrievals on snowfall, humidity field, vertical velocity field, divergence field, and cloud microphysical processes. The major results are: (1) the errors of AIRS retrieved surface air temperature products are largely systematic deviations, for which the influences of terrain altitude and surface types are the major reasons; (2) the differences between the AIRS atmospheric profile retrievals and T213 numerical prediction products in temperature are generally less than 2 K, the differences in relative humidity are generally less than 25%; and (3) the AIRS temperature and humidity retrieval products can adjust the model initial field, and thus can improve the capacity of snowfall simulation to some extent.     

大气红外探测器(AIRS)温、湿度反演产品的有效性检验及在数值模式中的应用研究

利用中国540个地面气象观测站点资料,对1和7月大气红外探测器(AIRS)的反演中国区域地面气温精度做了详细评估,分析了产生误差的原因。同时把AIRS的反演温、湿度廓线产品与T213数值预报产品进行比较,分析了它们之间的差异。为进一步考察AIRS温、湿度产品的有效性,我们把经过订正的AIRS地面气温以及温、湿度廓线产品分析同化到中尺度模式MM5中,用于华北降雪天气过程的对比模拟试验,分析AIRS反演产品对降雪量、水汽场、垂直速度场、散度场以及云物理过程等的影响。     

最高（低）温度PP法预报修正方案的比较研究

用EC850hPa温度数值预报格点值为参考做短中期的最高(低)温度预报是预报员常用的温度预报方法,本文提出了划分季节、划分有无降水和划分850hPa变温3种最高(低)温度PP法修正预报方案,并进行比较,找出最优方法,使最高(低)温度的预报精确度在原来的基础上有所提高.