The Atmospheric Boundary Layer Height Estimated From Multi-channel Microwave Radiometer Observation

By using the high temporal resolution temperature profile data observed from multi-channal microwave radiometer over the rice-wheat rotation cropping field observation site at Shouxian from July 2015 through May 2016, the atmospheric boundary layer heights are calculated with the potential temperature gradient method,and the diurnal, monthly and seasonal variation characteristics of the atmospheric boundary layer heights are studied,the results are compared with the ERA-Interim and NCEP FNL data product. The following results are obtained:(1) The atmospheric boundary layer height has a typical diurnal variation in the fine weather which is almost in the same phase of the diurnal temperature varistion, but it is not obvious in the cloudy weather and the height is lower, the ERA-Interim and NCEP FNL data have the same trends.(2) The averae largest height usually appears in afternoon during a day,with the largest value in August (more than 1520 meters) and smallest value in January (520 meters). The morning transition, highest height and time of average maximum height all has cyclical change, the evening transition is more distinct at 2000LST. As the less observation frequencies of ERA-Interim and NCEP FNL data every day, only highest height and evening transition have the same result.(3) During diurnal variations of season of the boundary layer, the height of the atmospheric boundary layer increased from winter, autumn to spring and summer,the fluctuation of the daytime changed greatly, and the nighttime period was more stable. The ERA-Interim and NCEP FNL were greater than the average Value during day time, while smaller than the observed values during the nighttime.(4) The average height of the boundary layer is largest in August (543 meters) and smallest in October (262 meters), ERA-Interim and NCEP FNL data are greater than the observed values except for in August. The average atmospheric boundary layer height is 436 meters in spring (March-May), 499 meters in summer (June-August),377 meters in autumn (September-November), 322 meters in winter(December-February). ERA-Interim and NCEP FNL data have the largest height in spring, and the second largest in summer, but the second smallest in autumn, and the smallest in winter.The above results show that the height of the boundary layer has obvious daily,monthly and seasonal evolution, which provides an important basis for us to understand the evolution of the boundary layer and to understand the reliability and accuracy of the existing numerical model dataset.