合肥整层大气可降水量与地面露点相关性分析

Correlation Analyses on Total Precipitable Water and Surface Dew Point Temperature over Hefei

根据合肥站地基双频微波辐射计和地面温、湿度传感器的4年观测资料,对比分析了国内外学者利用地面露点温度td计算整层大气可降水量W的经验计算模式。结果表明,合肥站td与lnW之间年线性相关系数普遍>0.90,经验系数a=-0.521,b=0.0901℃-1,反映出合肥地区气候条件的特殊性。td与lnW之间月相关系数的变化范围较大(0.120～0.813),而且秋季和冬季各月相关性较好,晚春和夏季各月相关性较差,尤其是在7、8月份;两者的季节相关性为秋季最好,夏季最差,春季和冬季的相关系数差别很小;经验系数a与月相关系数的年变化近似呈反向,在春、秋、冬三季变化比较平缓,在夏季却出现剧烈变动。在月时间尺度上根据经验计算模式利用td计算W的方法不可取。

Based on four-year-observation using ground-based dual-channel microwave radiometer WVR--1100 and temperature/humidity sensors at Hefei station, the empirical relation between surface dew point td and total precipitable water W on the basis of mean daily values have been statistically analyzed. The calculated results show that the correlation coefficient r between surface ta and the natural logarithm of W is higher than 0. 90 and the value of empirical coefficients a and b are --0. 521 and 0. 0901℃^-1, respectively, mirroring particularity of the climate condition of Hefei region. The monthly correlation coefficients range from 0. 120 to 0. 813 and seasonal values from 0. 740 to 0. 865, with the highest value in fall and lowest in summer. The degree of correlation is excellent in fall and winter months, but weaker in late spring and summer months, especially for July and August. The monthly variations of a are gently during spring, fall and winter months, but acutely during the summer months. It＇s annual variation is nearly reverse to that of monthly correlation coefficient. Proposed that it is not advisable to calculate W using surface td based on empirical calculating model on monthly scale.