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Investigating the variation of intra-seasonal rainfall characteristics in Sierra Leone
The rainy season in Sierra Leone is unimodal from April to October; an understanding of the inter-annual variability of rainfall in Sierra Leone is of importance to economic sectors such as fisheries, agriculture, infrastructure, hydro-electric power generation (HEP) and water resources. This study investigated the variation of the intra-seasonal rainfall characteristics in Sierra Leone. Daily rainfall data from 4 synoptic stations was obtained from the Sierra Leone Meteorological Department from 1990-2014.
Published by: University of Nairobi - Department of Meteorology ; 2016
The rainy season in Sierra Leone is unimodal from April to October; an understanding of the inter-annual variability of rainfall in Sierra Leone is of importance to economic sectors such as fisheries, agriculture, infrastructure, hydro-electric power generation (HEP) and water resources. This study investigated the variation of the intra-seasonal rainfall characteristics in Sierra Leone. Daily rainfall data from 4 synoptic stations was obtained from the Sierra Leone Meteorological Department from 1990-2014.
Notes: If you wish to download the full text, please contact the author (mohamedyangbay2010(at)yahoo.com.) or library(at)wmo.int (Please replace (at) by @).
Language(s): English
Format: Digital (Available online for logged-in users)Tags: Seasonal change ; Precipitation ; Sierra Leone ; Thesis - WMO Fellowship Division
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CAWCR technical report, 48. Seasonal Climate Prediction in the Pacific using the POAMA coupled model forecast system
Cottrill A.; Hendon Harry H.; Lim Eun-Pa; et al. - Centre for Australian Weather and Climate Research, 2012The tropical Pacific Ocean basin is home to over 20 Pacific Island nations, many of which are sensitive to climate extremes from the El Niño-Southern Oscillation (ENSO) and rainfall variability associated the Inter-Tropical Convergence Zone and the South Pacific Convergence Zone. These Pacific Island countries are highly dependent on agriculture, fishing and tourism as a major source of food production and income, which can vary greatly depending on the weather and climate experienced from year to year. Hence, the provision of skilful seasonal forecasts is important to allow these countries to ...
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Available online: https://www.cawcr.gov.au/publications/
A. Cottrill ; Harry H. Hendon ; Eun-Pa Lim ; Sally Langford ; Y. Kuleshov ; Andrew Charles ; David Jones
Published by: Centre for Australian Weather and Climate Research ; 2012The tropical Pacific Ocean basin is home to over 20 Pacific Island nations, many of which are sensitive to climate extremes from the El Niño-Southern Oscillation (ENSO) and rainfall variability associated the Inter-Tropical Convergence Zone and the South Pacific Convergence Zone. These Pacific Island countries are highly dependent on agriculture, fishing and tourism as a major source of food production and income, which can vary greatly depending on the weather and climate experienced from year to year. Hence, the provision of skilful seasonal forecasts is important to allow these countries to prepare for changes in rainfall and impending droughts associated with the changes in ENSO. The Australian Bureau of Meteorology has developed a dynamical seasonal forecast system POAMA (Predictive Ocean-Atmosphere Model for Australia), which is a state of the art seasonal to inter-annual forecast system based on a coupled model of the ocean and atmosphere. The model has good skill at predicting El Niño and La Niña up to 9 months in advance and it is capable of simulating the spatial and temporal variability of tropical rainfall associated with ENSO. Consequently, the variability of rainfall patterns across the Pacific region is skilfully predicted by POAMA at short lead times. The availability of seasonal forecasts from dynamical models will aid Pacific Island countries to improve economic returns in agriculture and other industries and reduce impacts from storms, floods and droughts associated with the extremes of El Niño and La Niña.
Collection(s) and Series: CAWCR technical report- No. 48
Language(s): English
Format: Digital (Free)Tags: Observations ; Seasonal change ; Climate ; Climate model ; Climate prediction ; Weather forecasting ; Region V - South-West Pacific
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Spatial Distributions of Atmospheric Radiative Fluxes and Heating Rates over China during Summer
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Yang Da-Sheng; Wang Pu-Cai - Science Press, 2010The latitude-altitude distributions of radiative fluxes and heating rates are investigated by utilizing CloudSat satellite data over China during summer. The Tibetan Plateau causes the downward shortwave fluxes of the lower atmosphere over central China to be smaller than the fluxes over southern and northern China by generating more clouds. The existence of a larger quantity of clouds over central China reflects a greater amount of solar radiation back into space. The vertical gradients of upward shortwave radiative fluxes in the atmosphere below 8 km are greater than those above 8 km. The la ...
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Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10016
in Atmospheric and Oceanic Science Letters > Volume 3 Number 5 (16 September 2010) . - p.248-251The latitude-altitude distributions of radiative fluxes and heating rates are investigated by utilizing CloudSat satellite data over China during summer. The Tibetan Plateau causes the downward shortwave fluxes of the lower atmosphere over central China to be smaller than the fluxes over southern and northern China by generating more clouds. The existence of a larger quantity of clouds over central China reflects a greater amount of solar radiation back into space. The vertical gradients of upward shortwave radiative fluxes in the atmosphere below 8 km are greater than those above 8 km. The latitudinal-altitude distributions of downward longwave radiative fluxes show a slantwise decreasing trend from low latitudes to high latitudes that gradually weaken in the downward direction. The upward longwave radiative fluxes also weaken in the upward direction but with larger gradients. The maximum heating rates by solar radiation and cooling rates by longwave infrared radiation are located over 28-40°N at 7-8 km mean sea level (MSL), and they are larger than the rates in the northern and southern regions. The heating and cooling rates match well both vertically and geographically.
Language(s): English
Format: Digital (Free), Hard copyTags: Atmosphere ; Summer ; Thermal radiation ; Weather ; Seasonal change ; China
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Temporal Variations of the Frontal and Monsoon Storm Rainfall during the First Rainy Season in South China
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Yuan Fang; Wei Ke; Chen Wen; et al. - Science Press, 2010The temporal variations in storm rainfall during the first rainy season (FRS) in South China (SC) are investigated in this study. The results show that the inter-annual variations in storm rainfall during the FRS in SC seem to be mainly influenced by the frequency of storm rainfall, while both frequency and intensity affect the inter-decadal variations in the total storm rainfall. Using the definitions for the beginning and ending dates of the FRS, and the onset dates of the summer monsoon in SC, the FRS is further divided into two sub-periods, i.e., the frontal and monsoon rainfall periods. T ...
[article]Temporal Variations of the Frontal and Monsoon Storm Rainfall during the First Rainy Season in South China
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Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10010
Fang Yuan ; Ke Wei ; Wen Chen ; Soi Kun Fong ; Ka Cheng Leong
in Atmospheric and Oceanic Science Letters > Volume 3 Number 5 (16 September 2010) . - p.243-247The temporal variations in storm rainfall during the first rainy season (FRS) in South China (SC) are investigated in this study. The results show that the inter-annual variations in storm rainfall during the FRS in SC seem to be mainly influenced by the frequency of storm rainfall, while both frequency and intensity affect the inter-decadal variations in the total storm rainfall. Using the definitions for the beginning and ending dates of the FRS, and the onset dates of the summer monsoon in SC, the FRS is further divided into two sub-periods, i.e., the frontal and monsoon rainfall periods. The inter-annual and inter-decadal variations in storm rainfall during these two periods are investigated here. The results reveal a significant out-of-phase correlation between the frontal and monsoon storm rainfall, especially on the inter-decadal timescale, the physical mechanism for which requires further investigation.
Language(s): English
Format: Digital (Free), Hard copyTags: China ; Monsoon ; Precipitation ; Weather ; Seasonal change
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Marine Atmospheric Boundary Layers Associated with Summer Monsoon Onset over the South China Sea in 1998
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Wang Dong-Xiao; Zhou Wen; Yu Xiao-Li; et al. - Science Press, 2010The variations of the marine atmospheric boundary layer (MABL) associated with the South China Sea Summer Monsoon were examined using the Global Positioning System (GPS) sounding datasets obtained four times daily during May-June 1998 on board Research Vessels Kexue 1 and Shiyan 3. The MABL height is defined as the height at the lowest level where virtual potential temperature increases by 1 K from the surface. The results indicate that the MABL height decreased over the northern South China Sea (SCS) and remained the same over the southern SCS, as sea surface temperature (SST) fell for the no ...
[article]Marine Atmospheric Boundary Layers Associated with Summer Monsoon Onset over the South China Sea in 1998
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Available online: http://www.iapjournals.ac.cn/aosl/ch/reader/view_abstract.aspx?file_no=AOSL10039
Dong-Xiao Wang ; Wen Zhou ; Xiao-Li Yu ; Quiang Xie ; Xin Wang
in Atmospheric and Oceanic Science Letters > Volume 3 Number 5 (16 September 2010) . - p.263-270The variations of the marine atmospheric boundary layer (MABL) associated with the South China Sea Summer Monsoon were examined using the Global Positioning System (GPS) sounding datasets obtained four times daily during May-June 1998 on board Research Vessels Kexue 1 and Shiyan 3. The MABL height is defined as the height at the lowest level where virtual potential temperature increases by 1 K from the surface. The results indicate that the MABL height decreased over the northern South China Sea (SCS) and remained the same over the southern SCS, as sea surface temperature (SST) fell for the northern and rose for the southern SCS after the monsoon onset. Over the northern SCS, a decrease in both the SST and the surface latent-heat flux after the onset resulted in a reduction of the MABL height as well as a decoupling of MABL from clouds. It was found that MABL height reduction corresponded to rainfall occurrence. Over the southern SCS, a probable reason for the constant increase of SST and surface heat flux was the rainfall and internal atmospheric dynamics.
Language(s): English
Format: Digital (Free), Hard copyTags: China ; Ocean-atmosphere interaction ; Monsoon ; Weather ; Seasonal change
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Interannual Variability of Snow Depth over the Tibetan Plateau and Its Associated Atmospheric Circulation Anomalies
The interannual variability of wintertime snow depth over the Tibetan Plateau (TP) and related atmospheric circulation anomalies were investigated based on observed snow depth measurements and NCEP/NCAR reanalysis data. Empirical orthogonal function (EOF) analysis was applied to identify the spatio-temporal variability of wintertime TP snow depth. Snow depth anomalies were dominated by a monopole pattern over the TP and a dipole structure with opposite anomalies over the southeastern and northwestern TP. The atmospheric circulation conditions responsible for the interannual variability of TP s ...
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Understanding the predictabilty and seasonal rainfall variability patterns during OND and JFM over DRCongo
The objective of this work is thus to enhance an understanding on the regional and global patterns that may contribute to the knowledge of the variability and predictability of OND and JFM rains season over DRC for a better prediction of the rains season and also to improve the DRC seasonal models for a better decisions makers, and also assist potentials users on their needs.
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Long-range forecasting Research report, 06. Proceedings of the first WMO Workshop on the Diagnosis and Prediction of Monthly and Seasonal Atmospheric Variations over the Globe : volume I and II
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Commission for Aerology (CAe). Seasonal peculiarities of the temperature and atmospheric circulation regimes in the Arctic and Antarctic : (working paper prepared for the third session of the Commission for Aerology)
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