Multi-Layered Cloud Distribution Over Tropical Station Using Radiosonde Humidity Observations and CloudSat Measurements

Kandula V Subrahmanyam,Karanam Kishore Kumar

doi:10.5539/enrr.v9n3p9

Abstract

Owing to its importance of role played by multi-layered clouds in climate of earth&rsquo;s atmosphere, a decadal observation (January, 2000 to December, 2009) from India Meteorological Department, Trivandrum regular radiosonde (00 &amp; 12 UTC) ascents and CloudSat observations were used to study the distribution of multi-layered cloud formation at this location. Both the ground and space based observations at Trivandrum locations shows the more or less same percentage of occurrence of single-, double-, three-, four- and five-layered clouds. The important findings are: Radiosonde derived cloud ‐free cases and one to five cloud layers account for 30.63%, 42.51%, 19.76%, 5.85%, 1.08%, and 0.16% all cases, respectively, whereas CloudSat shows 47.17%, 24.74%, 6.41%, 1.81%, 0.13% of the total samples, respectively. In general, the thickness of cloud layers does not change much from summer to winter. However, the occurrences of multi-layered clouds are more frequent in the summer. Further, keeping the CloudSat limitations in view, an attempt is made to evaluate the CloudSat observations using radiosonde measurements and which has the great potential for studying the multi-layered cloud structures over the globe and important in climate point of view.

Highlights

Clouds play an important role in regulating the earth’s atmosphere by changing the energy through its horizontal and vertical distribution
Changes in cloud vertical structure depends on the locations of cloud top and base, number of cloud layers and thickness, which affects the atmospheric circulation in atmospheric general circulation models (GCMs) by modifying the distribution of atmospheric latent heating rates (Randall et al, 1989; Wang et al, 1999)
Derived the first comprehensive cloud vertical structure data set at Trivandrum from radiosonde and space based CloudSat observations

Summary

Introduction

Clouds play an important role in regulating the earth’s atmosphere by changing the energy through its horizontal and vertical distribution. There have been a considerable amount of studies in the past on cloud vertical structure distribution (Wang et al, 2000; Jin et al, 2007; Zhang et al, 2010) and which emphatically showed the cloud effects on the general circulation (Wang & Rossow, 1998). They have examined the response of the atmospheric circulation by varying the cloud vertical distributions in the models. The present study presents the climatological distribution of multi-layer cloud structure over Trivandrum using one decadal radiosonde humidity observations and CloudSat observations

Data and Methodology

Results and Discussion

Conclusion