Cloud Characteristics over Arctic from CALIPSO-CloudSat measurements during 2006 - 2017
Abstract
Arctic clouds play a key role in Arctic climate by changing surface and atmospheric radiation, but ground-based and aircraft measurements have been difficult to conduct due to the harsh environment. Space-based passive sensor observations of clouds are also hard because of the absence of solar insolation and weak differences in albedo and temperature between surface and atmosphere. However, active sensor satellites, CALIPSO and CloudSat, enable the analysis of the three-dimensional distribution of Arctic clouds despite their narrow field-of-view.
In this study, 11-year (2006-2017) measurements of CALIPSO and CloudSat are analyzed to investigate the three-dimensional distribution of Arctic clouds and their optical and microphysical properties. During the period, the averaged cloud fraction (CF) over Arctic (>60°N) from CALIPSO is 0.75, showing maximum (0.9) over Greenland Sea and Barents Sea and minimum (0.5) over Northern Greenland. CF from CloudSat shows similar distribution, but is lower than that of CALIPSO, due to the different wavelength of two sensors. And active sensors detect more (less) clouds over sea ice (open ocean) compared to MODIS. Cloud optical depth (COD) from CALIPSO has a distribution similar to that of CF, except for Bering Strait and Chukchi Sea. Since the North Atlantic region is open ocean even in winter, large amount of water vapor supply from ocean results in high cloud water content (CWC) over the region. From the vertical distribution of CF, calculated from CALIPSO, over north of 70°N, CF under 3 km shows high in fall and low in summer, which results from temperature difference between atmosphere and ocean, while COD is highest in summer. Ice water content (IWC) and liquid water content (LWC) from CloudSat have out of phase, but LWC dominates IWC, which leads to highest CWC during summer.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A24K..18Y
- Keywords:
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- 0399 General or miscellaneous;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0434 Data sets;
- BIOGEOSCIENCESDE: 0799 General or miscellaneous;
- CRYOSPHEREDE: 4299 General or miscellaneous;
- OCEANOGRAPHY: GENERAL