Aerosols
; Arid regions
; Atmospheric aerosols
; Image reconstruction
; Radiometers
; Satellite imagery
; Ultraviolet spectrometers
; Aerosol optical property
; Aerosol robotic networks
; Back trajectory analysis
; East Africa
; Moderate resolution imaging spectroradiometer
; MODIS
; NDVI
; Ozone monitoring instruments
; Optical properties
; AERONET
; aerosol
; climate modeling
; longitudinal gradient
; model validation
; MODIS
; monitoring system
; NDVI
; optical depth
; SIR
; spatial resolution
; spatiotemporal analysis
; surface reflectance
; trend analysis
; uncertainty analysis
; vegetation cover
; absorption
; aerosol
; Article
; climate
; Kenya
; optical depth
; optics
; priority journal
; season
; sensor
; spatiotemporal analysis
; surface property
; Tanzania
; Uganda
; vegetation
; Eastern Desert
; Egypt
; Indian Ocean
; Kenya
; Tanzania
; Uganda
Scopus学科分类:
Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要:
The present study is aimed at analyzing spatial and temporal characteristics of aerosols retrieved from MODerate resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI) sensors over East Africa (EA). Data spanning for a period of 15 years during 2001–2015 was used to investigate aerosol optical depth (AOD550), �ngstrom exponent (AE470-660) and absorption aerosol Index (AAI) over EA and selected locations within EA. Validation results of MODIS-Terra versus the Aerosol Robotic NETwork (AERONET) AOD550revealed that the former underestimated aerosol loading over the studied regions due to uncertainties in surface reflectance. The annual mean AOD550, AAI, and AE470-660were found to be 0.20 � 0.01, 0.81 � 0.03, and 1.39 � 0.01, respectively with peak values observed during the local dry seasons. The spatial seasonal distributions of mean AOD550suggested high (low) values during the local dry (wet) periods. The high AOD values found along the borders of southwest of Uganda were attributed to smoke particles; while higher (lower) values of AE470-660(AAI) dominated most parts of the study domain. Low AOD (0.1–0.2) centers were located in high-altitude regions with relatively high vegetation cover over western and central parts of Kenya, and central and northern parts of Tanzania. Furthermore, latitudinal and longitudinal gradients in AOD550showed a “southern low and northern high” and a “western low and eastern high” profile, respectively during JJA, as other seasons showed heterogeneous variations. Trend analysis revealed a general increase in AOD and AAI and a decrease in AE; while impact factors significantly affected AOD distribution over EA. HYSPLIT back trajectory analyses revealed diverse transport pathways originated from the Arabian Deserts, central Africa, and southwest of Indian Ocean along with locally produced aerosols during different seasons. � 2016 Elsevier Ltd
Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), International Joint Laboratory on Climate and Environment Change (ILCEC), Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, China; Department of Physical Sciences, Meru University of Science and Technology, P.O. Box 972-60200, Meru, Kenya
Recommended Citation:
Boiyo R,, Kumar K,R,et al. Climatological analysis of aerosol optical properties over East Africa observed from space-borne sensors during 2001–2015[J]. Atmospheric Environment,2017-01-01,152