b. Degree of Convective Aggregation
Different metrics have been used to quantify the degree of aggregation
under different circumstances such as the “organization index” that
detects organized convective features using satellite observed infrared
brightness temperatures (Bony et al., 2020; Tompkins & Semie, 2017),
subsidence fraction (Coppin & Bony, 2015), the spatial variance of
column relative humidity (Wing & Cronin, 2016) and the spatial variance
of column integrated water vapor (Dai & Soden, 2020; Wing et al.,
2020). In this study, we characterize the spatial organization of
convection using subsidence fraction, which is computed as the
fractional area covered by subsidence based on daily vertical pressure
velocity at 500 hPa \(\left(\omega_{500}\right)\). We note that using
the spatial variance of column integrated water vapor yields similar
results.