TITLE:
Long-Term Assessment of the Spatial Temporal Trends in Selected Cloud Physical Properties over the Three Distinct Sites in Kenya
AUTHORS:
Sostine N. Makokha, John W. Makokha, Festus B. Kelonye
KEYWORDS:
MODIS, MERRA-2, CF, CER, CTP, CTT Seasons and Clouds Physical Properties
JOURNAL NAME:
Open Access Library Journal,
Vol.9 No.12,
December
30,
2022
ABSTRACT: The presence of clouds in the Earth’s atmosphere plays a pivotal role in regulating the Earth’s energy budget. Increased anthropogenic activities and emissions can significantly lead to changes in cloud composition and cloud structure affecting the clouds physical characteristics, hence causing alterations in the climatic conditions over Kenya. Given this, the present study examined the spatial temporal physical properties of clouds over three study sites, by paying a special consideration on cloud parameters, such as: Cloud Effective Radius (CER), Cloud Top Pressure (CTP), Cloud Top Temperature (CTT) and the Cloud Fraction (CF). These cloud parameters were retrieved from the MODerate resolution Imaging Spectroradiometer (MODIS) sensor and the Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) model between January 2005 and December 2020. The data retrieved on clouds physical properties was utilized to estimate the trends and spatial variations and assess their statistical significance on climate over the study domain. The Spatial patterns of seasonal mean of cloud parameters from the sensors and the model were generally characterized with positive and negative trends over Kenya observed during the four seasons. Trends in CER were found as follows: Nairobi (0.04, 0, -0.04 and -0.01) for the four seasons respectively, Malindi (0.04, 0.01, 0.04 and 0.01) and lastly Mbita (-0.06, -0.06, 0.04 and -0.05); for CTT, Nairobi, -0.1, -0.2, -0.1 and -0.2, Malindi, 0.1, -0.2, 0.1 and 0.05 and Mbita, 0.2, 0.2, -0.2 and 0.15 respectively for every season. Trends in CTP were observed to vary seasonally as follows: Nairobi -0.5, -1, 0.5 and -0.5, Malindi -0.5, -3, 1, and 0.5 and lastly Mbita 0.5, 0, -1 and -1 respectively. And finally, the spatial trends in CF observed over the four seasons over the study domains were obtained a follows: Nairobi (0.3, 0, -0.002 and 0), Malindi (0.3, 0.002, 0 and 0.001) and lastly for Mbita (0.3, 0.003, 0.001 and 0.001) respectively for the four seasons of the study. Spatial trends in the selected cloud properties were determined and observed to vary both seasonally and regionally. The study revealed patterns of trends in physical cloud properties and formed a basis for further research on clouds over Kenya.