Influence of dust extinction coefficient on the ice-cloud fraction over high-latitudes with CALIPSO
Abstract
Clouds have considerable effects on climate by hydrological processes through rain and snow, and by radiative processes through reflection of solar radiation and absorption of infrared radiation. In particular, the cloud thermodynamic phase (water droplet/ice crystal, hereafter cloud phase) is known to influence cloud radiative properties, for example, optical depth, single scattering albedo and emissivity. Because dust particles serve as ice nuclei and change ice cloud physical properties, it is of quite importance to examine the influence of dust on the ice-cloud fraction. Also, High-latitudes and polar regions are known to be sensitive to the global warming. This study examines the relationship between dust amount and determination of cloud phase over high-latitudes using CALIPSO data. Dust extinction coefficient is used as a measure of dust amount in this study. Both dust extinction coefficient and cloud phase information are derived from the active sensor (CALIOP) on board CALIPSO satellite. Objective archives of temperature and height profiles from ECMWF were also used. As a result of comparing dust extinction coefficient with the thermodynamic phase of the underlying cloud layer, we found that the ice-cloud fraction increased with dust extinction coefficient for the similar temperature range. It is interesting to note the dependence of non-quantitative parameter of the cloud phase on the dust extinction coefficient. Other analyses will be shown at the presentation such as relationship of height - ice cloud fraction for different dust extinction coefficients, its geographical features, and so on. This sort of basic knowledge on the cloud physics would contribute to improving the accuracy of numerical model simulations for the future climate.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A53R2957K
- Keywords:
-
- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES;
- 3355 Regional modeling;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 1626 Global climate models;
- GLOBAL CHANGE