地基红外测云仪探测能力分析

利用地基红外测云仪(WSIRCMS)在2011年11月北京观象台的连续观测数据,从总云量、云底高和天空类型3个方面初步分析其探测能力。结果表明:1该仪器能够不分昼夜同时实现云高、云量(高、中、低和总云量)和天空类型的连续自动探测;2与参考标准云量的差值在±10%以内的样本数占总样本数的72.5%,有霾存在时,对中高云的观测能力较弱,造成云量观测结果差异较大;3与激光云高仪的天顶方向的无云一致率达94.9%;在中低云情况下,云高观测结果一致性较好,高云时存在较大差异,WSIRCMS观测云高偏高;4与人工分类的天空类型一致的样本数占总样本数的82.63%,对波状云、积状云和混合云的识别能力稍低。

Detectability Analysis of New Ground Based Infrared Instrument

The analysis is based on the data collected continually by WSIRCMS at Beijing Meteorological Observatory in November 2011. The analysis aims to evaluate preliminarily the detectability of WSIRCMS on total cloud cover, cloud base height, and sky types. The results indicate: (1) The instrument can conduct continuous automatic detection day and night towards cloud height, cloud cover (includes high, medium, low and total cloud cover) as well as sky types. (2) Samples whose difference from the reference standards is within ±10%, account for 72.5% of the total sample. The detection capability towards medium and high clouds is weaker when haze happens, which leads to great differences among observations of cloud covers. (3) When there is no cloud, the data consistency of results from WSIRCMS and ceilometers reaches 94.9%. The observed results conform fairly well under the condition of low or medium clouds. But towards high clouds, the observed results from WSIRCMS are higher than those from ceilometers. (4) Samples that conform with results of sky types under manual classification account for 82.63% of the total sample, but WSIRCMS does not show high identification capability towards undulates clouds, cumuliform clouds, and mixed clouds.