Investigation of the adiabatic assumption for estimating cloud micro- and macrophysical properties from satellite and ground observations

47Citations
Citations of this article
52Readers
Mendeley users who have this article in their library.

Abstract

Cloud properties from both ground-based as well as from geostationary passive satellite observations have been used previously for diagnosing aerosol-cloud interactions. In this investigation, a 2-year data set together with four selected case studies are analyzed with the aim of evaluating the consistency and limitations of current ground-based and satellite-retrieved cloud property data sets. The typically applied adiabatic cloud profile is modified using a sub-adiabatic factor to account for entrainment within the cloud. Based on the adiabatic factor obtained from the combination of ground-based cloud radar, ceilometer and microwave radiometer, we demonstrate that neither the assumption of a completely adiabatic cloud nor the assumption of a constant sub-adiabatic factor is fulfilled (mean adiabatic factor 0.63±0.22). As cloud adiabaticity is required to estimate the cloud droplet number concentration but is not available from passive satellite observations, an independent method to estimate the adiabatic factor, and thus the influence of mixing, would be highly desirable for global-scale analyses. Considering the radiative effect of a cloud described by the sub-adiabatic model, we focus on cloud optical depth and its sensitivities. Ground-based estimates are here compared vs. cloud optical depth retrieved from the Meteosat SEVIRI satellite instrument resulting in a bias of -4 and a root mean square difference of 16. While a synergistic approach based on the combination of ceilometer, cloud radar and microwave radiometer enables an estimate of the cloud droplet concentration, it is highly sensitive to radar calibration and to assumptions about the moments of the droplet size distribution. Similarly, satellite-based estimates of cloud droplet concentration are uncertain. We conclude that neither the ground-based nor satellite-based cloud retrievals applied here allow a robust estimate of cloud droplet concentration, which complicates its use for the study of aerosol-cloud interactions.

References Powered by Scopus

Light scattering in planetary atmospheres

2202Citations
N/AReaders
Get full text

Overview of the CALIPSO mission and CALIOP data processing algorithms

1865Citations
N/AReaders
Get full text

The cloudsat mission and the A-Train: A new dimension of space-based observations of clouds and precipitation

1846Citations
N/AReaders
Get full text

Cited by Powered by Scopus

Remote Sensing of Droplet Number Concentration in Warm Clouds: A Review of the Current State of Knowledge and Perspectives

218Citations
N/AReaders
Get full text

Constraining the aerosol influence on cloud liquid water path

135Citations
N/AReaders
Get full text

Reviews and perspectives of high impact atmospheric processes in the Mediterranean

98Citations
N/AReaders
Get full text

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Cite

CITATION STYLE

APA

Merk, D., Deneke, H., Pospichal, B., & Seifert, P. (2016). Investigation of the adiabatic assumption for estimating cloud micro- and macrophysical properties from satellite and ground observations. Atmospheric Chemistry and Physics, 16(2), 933–952. https://doi.org/10.5194/acp-16-933-2016

Readers over time

‘15‘16‘17‘18‘19‘20‘21‘22‘23‘24‘25036912

Readers' Seniority

Tooltip

Researcher 19

49%

PhD / Post grad / Masters / Doc 17

44%

Professor / Associate Prof. 3

8%

Readers' Discipline

Tooltip

Earth and Planetary Sciences 29

74%

Environmental Science 5

13%

Physics and Astronomy 3

8%

Agricultural and Biological Sciences 2

5%

Save time finding and organizing research with Mendeley

Sign up for free
0