东北高空湿度变化特征及其与地面气温和降水的关系

利用1971~2005年探空和地面观测资料,详细分析了东北地区高空比湿和相对湿度的时空变化特征,并探讨了比湿和相对湿度与地面气温、降水量的关系。结果表明：东北地区比湿空间分布主要受到水汽来源的影响,地面由东南向西北递减,高空由南向北递减;相对湿度受水汽、海拔高度和纬度的共同影响,地面和对流层下层由南向北先减后增,对流层中层由南向北递增,赤峰向通辽延伸的西南-东北向干舌地面最明显,随高度增加逐渐减弱。1971~2005年,东北地区比湿从地面到高空均为增加趋势,对流层中下层的增加趋势更加显著;相对湿度在地面呈显著减小趋势,对流层中层呈显著增加趋势。大气比湿与地面气温在年、季尺度上存在一致的显著正相关关系,大气相对湿度与地面气温在季节尺度上存在显著负相关关系;对流层中下层相对湿度与降水量相关最显著;地面气温升高对东北气候趋于干旱化起了重要作用,高空相对湿度增加有利于降水增加,气温与比湿的相互消长,影响了气候的干、湿变化。

Climate Change Characteristics of Free Atmospheric Humidity and Its Relationship with Temperature and Precipitation in Northeast China

In accordance with the data of radio sounding data and the data of surface temperature and precipitation in Northeast China in 1971-2005, the temporal and spatial change characteristics of free atmospheric specific humidity and relative humidity as well as the relationship between humidity and surface temperature and precipitation are analyzed. The results indicate that, the spatial distribution of specific humidity is impacted by water vapor source in Northeast China, decreased from the southeast to the northwest on the ground, and decreasing from the south to the north at upper air. The spatial distribution of relative humidity is impacted by water vapor, altitude and latitude, decreased firstly and then increased from the south to the north from the ground to lower layer of troposphere, increased from the south to the north in the mid layer of troposphere, and the southwest-northeast drought tongue from Chifeng to Tongliao is the most obvious, and gradually weakened with height increased. In 1971-2005, annual and seasonal specific humidity exhibited increasing trends from the ground to upper air, the increasing trends in the mid to lower layer of troposphere. The annual and seasonal relative humidity decreases significantly on the ground , and increases significantly in the mid layer of troposphere. The positive correlation between free atmospheric specific humidity and surface temperature is significant on annual and seasonal time scales. The negative correlation between free atmospheric relative humidity and surface temperature is significant on seasonal time scales. The correlation between relative humidity in the mid and lower layer of troposphere and precipitation is significant. The increased temperature is played an important role in climate changing to aridity of Northeast China. The increase of upper relative humidity helps add precipitation. The changes of surface temperature and water vapor content have impact the change of drought and humid climate.