Measuring the variability of the shallow convective mass flux profiles in the tropical trade wind region
- 1Max-Planck-Institut für Meteorologie, Atmosphäre im Erdsystem, Hamburg, Germany
- 2University of Hamburg, Hamburg, Germany
Mass flux is a key parameter to represent shallow convection in global circulation models. To estimate the shallow convective mass flux as accurately as possible, observations of this parameter are necessary. Prior studies from Ghate et al. (2011) and Lamer et al. (2015) used Doppler radar measurements over a few months to identify a typical shallow convective mass flux profile based on cloud fraction and vertical velocity. In this study, we extend their observations by using long term remote sensing measurements at the Barbados Cloud Observatory (13° 09’ N, 59° 25’ W) over a time period of 30 months and check a hypothesis by Grant (2001), who proposed that the cloud base mass flux is just proportional to the sub-cloud convective velocity scale. Therefore, we analyze Doppler radar and Doppler lidar measurements to identify the variation of the vertical velocity in the cloud and sub-cloud layer, respectively. Furthermore, we show that the in-cloud mass flux is mainly influenced by the cloud fraction and provide a linear equation, which can be used to roughly calculate the mass flux in the trade wind region based on the cloud fraction.
References:
Ghate, V. P., M. A. Miller, and L. DiPretore, 2011: Vertical velocity structure of marine boundary layer trade wind cumulus clouds. Journal of Geophysical Research: Atmospheres, 116 (D16), doi:10.1029/2010JD015344.
Grant, A. L. M., 2001: Cloud-base fluxes in the cumulus-capped boundary layer. Quarterly Journal of the Royal Meteorological Society, 127 (572), 407–421, doi:10.1002/qj.49712757209.
Lamer, K., P. Kollias, and L. Nuijens, 2015: Observations of the variability of shallow trade wind cumulus cloudiness and mass flux. Journal of Geophysical Research: Atmospheres, 120 (12), 6161–6178, doi:10.1002/2014JD022950.
How to cite: Klingebiel, M., Konow, H., and Stevens, B.: Measuring the variability of the shallow convective mass flux profiles in the tropical trade wind region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4780, https://doi.org/10.5194/egusphere-egu2020-4780, 2020.