Estimation of Radiative Forcing and Chore Length of Shallow Convective Clouds (SCC) Based on Broadband Pyranometer Measurements

We presented a method to identify and calculate cloud radiative forcing (CRF) and horizontal chore length (L) of shallow convective clouds (SCC) using broadband pyranometer measurements. The data analyzed were collected from the SCC campaign during two summers (2015-2016) at Baiqi site over the Inner Mongolia grassland. The SCC detection method was verified against observations from reports and cameras records. It was found that the results of the detection method and human observations were in agreement by about 75%. The deviation of L can be attributed to following factors:1) the accuracy of wind speed at the height of SCC and the ratio of horizontal to vertical length play a key role in determining the value of L; 2) the effect of variance in solar zenith angle can be negligible. The downwelling shortwave CRF of SCC was −134.1 W m⁻². The average value of L of SCC was 1129 m. Besides, the distribution of normalized cloud chore length agreed well with a power-law distribution.