Seasonal and interannual changes of Arctic MODIS cloud regimes
Abstract
One of the assumed mechanisms contributing to the Arctic's rapid warming is thought to be changes in local cloudiness. This presentation will introduce the Arctic cloud regimes (CRs) which are based on the classification of joint histograms of cloud top pressure and cloud optical thickness from Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites. A k-means clustering method is used to sort the histograms into six distinct CRs. By employing a compositing approach on data sets from satellites and reanalysis, we examine CR structural and thermodynamic characteristics. We find that the Arctic MODIS CRs tend to form within distinct dynamical and thermodynamic environments defined by area-weighted mean vertical profiles of atmospheric variables from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). Despite the perceived inferior quality of retrieved cloud properties from passive MODIS observations at high latitudes, the diverse shapes of collocated cloud vertical structures and reflectivity profiles from CloudSat/CALIPSO products are largely consistent with the passive cloud views. More importantly, the cloud radiative effects of each CR at the surface can be quantified by compositing radiative fluxes provided by the Clouds and the Earth's Radiant Energy System instrument (CERES) and CloudSat/CALIPSO. Links of the above to the seasonal and interannual variations of CR occurrence frequency and the relationship of the latter with recent changes of arctic climate and clouds will be discussed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A51P2455L
- Keywords:
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- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSESDE: 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 0738 Ice;
- CRYOSPHEREDE: 0750 Sea ice;
- CRYOSPHERE