Convective available potential energy (CAPE) in Northern Africa and tropical Atlantic and study of its connections with rainfall in Central and West Africa during Summer 1985

Monkam, David

doi:10.1016/s0169-8095(02)00006-6

Cited by 32 publications

(25 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DeMott and Randall (2004) have shown that the long-term changes in CAPE are associated with the changes in convective activity and rainfall. The study of CAPE in northern Africa and tropical Atlantic in summer by Monkam, (2002) show good correlation with rainfall in Central and West Africa around the ITCZ and towards some mountains. However, some observations by Thompson et al (1979) and Brown and Bretherton (1997) suggest that sustaining high CAPE value for a long time should be associated with decrease in rainfall because convective precipitation destroys the CAPE.…”

Section: Cape and Rainfall Relationshipmentioning

confidence: 79%

“…Higher values of CAPE seen at coastal and island stations may be due to availability of large moisture content in the boundary layer. Monkam (2002), in his study of CAPE in Northern Africa and the tropical Atlantic, has shown that the meteorological conditions that lead to vertical thermodynamic structures with large CAPE result from particular arrangements of geographical features. High values of CAPE observed in the foothills of the Himalayas may be due to orographic features of the region.…”

Section: Distribution and Trends Of Cape Over The Indian Regionmentioning

confidence: 99%

“…Zawadzki et al (1981), for a continental region of eastern Canada, have found large positive correlations between areal rainfall rates and CAPE. Over northern Africa and the tropical Atlantic region, Monkam (2002) has observed a good correlation between CAPE and rainfall around the ITCZ and towards some mountains. However, some studies report negative correlation between CAPE and rainfall.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Trends of Convective Available Potential Energy over the Indian region and its effect on rainfall

Murugavel

Pawar

Gopalakrishnan

2011

Intl Journal of Climatology

View full text Add to dashboard Cite

Many studies in recent times have suggested that long-term changes in Convective Available Potential Energy (CAPE) are associated with the changes in convective activity and atmospheric energy budget and, hence, the changes in CAPE could be used as a potential indicator of climate change. Here, we analyse daily radiosonde data of 32 stations over the Indian region from 1984 to 2008 (25 years), to study the climatology and long-term changes in CAPE, lower troposphere moisture content and upper tropospheric temperature. Using gridded daily rainfall data over this region, the relationship between average CAPE and average rainfall as well as the trends in CAPE and its effect on rainfall pattern are also examined during different seasons of this region. All the coastal and island stations, as well as some stations in the foothills of the Himalayas, show higher values of CAPE compared to other inland stations. This study clearly demonstrates that CAPE values have been systematically increasing over most parts of the Indian region during last 25 years. The increase in CAPE is found to be due to increase in low-level moisture content and decrease in upper level temperature over the last 25 years. The seasonal variations show that the CAPE is higher during the monsoon compared to pre-monsoon or post-monsoon seasons and it suggests that thermodynamic conditions favourable for high CAPE together with large-scale dynamics are necessary for organized monsoon convections over this region. In comparison with a large increase in the allIndia average of CAPE during monsoon season, which is about 38 J Kg −1 year −1 , the all-India summer monsoon rainfall increases about 1.3 mm year −1 . The systematic increasing trend in CAPE may be compensating for weakening of monsoon circulation and, thus, maintaining the monsoon rainfall over the Indian region.

show abstract

Section: Cape and Rainfall Relationshipmentioning

confidence: 79%

Section: Distribution and Trends Of Cape Over The Indian Regionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Trends of Convective Available Potential Energy over the Indian region and its effect on rainfall

Murugavel

Pawar

Gopalakrishnan

2011

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…The land-breeze front weakens, and the convective rainfall band along the coastal region diminishes. At the same time, the CAPE and latent and sensible heat fluxes in the inland area start to increase with surface heating [55][56][57]. In the late-afternoon hours, the contrast between land and sea surface temperature starts to increase again, but with the opposite sign to that in the early morning.…”

Section: Discussionmentioning

confidence: 96%

Diurnal Variation of Rainfall Associated with Tropical Depression in South China and its Relationship to Land-Sea Contrast and Topography

Yuchun

2013

Atmosphere

View full text Add to dashboard Cite

Convective precipitation associated with tropical depression (TD) is one primary type of post-flooding season rainfall in South China (SC). Observations of the Tropical Rainfall Measuring Mission (TRMM) satellite have shown specific diurnal features of convective rainfall in South China, which is somewhat different from that in other seasons or regions of China. Convective precipitation is usually organized into a rainfall band along the southeastern coast of South China in the early morning hours. The rainfall band develops and intensifies quickly in the morning, then moves inland in the afternoon and, finally, diminishes at night. The daily convective rainfall along the coast is much more than that in the inland region, and heavy rainfall is often found along the coast. A long-duration heavy rainfall event associated with tropical depression "Fitow" during the period from 28 August to 6 September 2001, is selected in this study to explore the diurnal feature of convective rainfall and its formation mechanism. Modeling results of the 10-day heavy rainfall event are compared with both rain-gauge observation and satellite-retrieved rainfall. Total precipitation and its spatial distribution, as well as diurnal variations are reasonably simulated and agree well with observations. Further analysis reveals that the development and movement of convective precipitation is mainly related to the land and sea breezes. The anomalous height-latitudinal circulation in the morning-to-noon hours is completely reversed in the afternoon-to-late-evening hours, with the convective rainfall swinging back and forth, following its updraft branch. Sensitivity experiments show that the afternoon convective rainfall in the inland region of SC is caused by the diurnal variation of solar radiation forcing. The mountain range along the coast and the complex topography in the inland region of SC plays a critical role in the enhancement of diurnal convective rainfall everywhere. The formation of a heavy rainfall band along the OPEN ACCESSAtmosphere 2014, 5 17 southeastern coast of SC and the diurnal variation of the rainfall pattern are mainly the results of the land-sea thermal contrast.

show abstract

“…CAPE stored in the atmosphere is activated if the value of CAPE is larger than that of CIN, that is, under real latent instability conditions. Therefore, climatological study of CAPE and CIN provides an insight into the strength of atmospheric convection (Monkam, 2002). 25…”

Section: Introductionmentioning

confidence: 99%

Climatological study of a new air stagnation index (ASI) for China and its relationship with air pollution

Huang

Cai

Wang

et al. 2018

Preprint

View full text Add to dashboard Cite

Abstract. Air stagnation index (ASI) is a vital meteorological measure of the atmosphere's ability to dilute air pollutants. The original metric adopted by US National Climatic Data Center (NCDC) is found not well suitable to China, because the decouple between upper and lower atmospheric layer results in a weak link between the near surface air pollution and upper-air wind speed. Therefore, a new threshold for ASI is proposed, consisting of daily 10 maximal ventilation in the atmospheric boundary layer, precipitation and real latent instability. In the present study, the climatological features of this newly defined ASI is investigated. It shows that the spatial distribution of the new ASI is similar to the original one; that is, annual mean stagnations occur most often in the northwest and southwest basins, i.e., Xinjiang and Sichuan basins (more than 180 days), and the least over plateaus, i.e., QinghaiTibet and Yunnan plateaus (less than 40 days). However, the seasonal cycle of the new ASI is changed. Stagnation 15 days under new metric are observed to be maximal in winter and minimal in summer, which is positively correlated with air pollution index (API) during 2000-2012. The correlation between ASI and concentration of fine particulate matter (PM2.5) during January 2013 of Beijing is also investigated. It shows that the new ASI matches the day-byday variation of PM2.5 concentration very well and is able to catch the haze episodes in that month. 20

show abstract

Convective available potential energy (CAPE) in Northern Africa and tropical Atlantic and study of its connections with rainfall in Central and West Africa during Summer 1985

Cited by 32 publications

References 16 publications

Trends of Convective Available Potential Energy over the Indian region and its effect on rainfall

Trends of Convective Available Potential Energy over the Indian region and its effect on rainfall

Diurnal Variation of Rainfall Associated with Tropical Depression in South China and its Relationship to Land-Sea Contrast and Topography

Climatological study of a new air stagnation index (ASI) for China and its relationship with air pollution

Contact Info

Product

Resources

About