The Change of Cloud Base Height over East Asia during 2010-2019

Cloud base height (CBH) is a key parameter in modulating surface radiation, atmospheric energy exchange, and climate feedback. However, few operational satellite CBH products are available, limiting studies on large-scale assessments of the change of CBH and of the relationship with surface and atmospheric conditions. This study presents a decadal CBH climatology over East Asia (2010-2019) using satellite remote sensing data (i.e., the MODIS Level-2 products) and a novel CBH retrieval algorithm that accurately retrieves CBH by converting cloud water path to geometric thickness via an effective cloud water content. The results reveal notable spatial, seasonal, and interannual variability. CBH increases notably in summer under monsoonal influence and warm, moist air masses, reaching 4.29 km in tropical oceans. In winter, it declines sharply under cold-air outbreaks, dropping to 0.35 km over northern and plateau regions. Strong positive correlations are found between CBH and both sea surface temperature (SST) and land surface temperature, with SST exhibiting a 2-month lag behind CBH. This temporal relationship suggests that cloud structure changes may influence ocean heat storage and provide predictive value for short-term SST trends. The dataset offers critical insight into CBH variation and is informative for improving cloud parameterizations and radiation feedback representation in climate models.