scholarly journals Study of secondary heat sources over India during southwest monsoon 2002

MAUSAM ◽  
2021 ◽  
Vol 58 (2) ◽  
pp. 213-228
Author(s):  
U. V. BHIDE ◽  
S. M. BAWISKAR ◽  
V. R. MUJUMDAR ◽  
P. V. PURANIK ◽  
S. P. GHANEKAR ◽  
...  
Keyword(s):  
Heat Source ◽  
Bay Of Bengal ◽  
Seasonal Variations ◽  
Seasonal Variability ◽  
Arabian Sea ◽  
Southwest Monsoon ◽  
Monsoon Circulation ◽  
Heat Sources ◽  
Drying Rates ◽  
The Impact

The southwest monsoon of 2002 has three unusual features viz., (i) delay in advance over westernmost parts of India by one month, (ii) absence of depressions/storms over Bay of Bengal and Arabian Sea and (iii) -51% departure of all India rainfall in July. These features of intra-seasonal variability have been studied in this paper. Apparent heat source (Q1) and apparent moisture sink (Q2) over Indian region have been estimated using daily NCEP-reanalysis data, for June - September 2002 to study the intra-seasonal variations of the secondary heat sources in relation to observed intra-seasonal variations of circulation and rainfall over India.The intensities of vertically integrated heat source < Q1 > and moisture sink < Q2 > are found to coincide with the excess rainfall zone over India in June 2002, whereas the intensities of < Q1 > and < Q2 > over central parts of the country in July 2002 are not comparable. This indicates absence of convective rainfall and increased sensible heating over India in July. The x-t diagram of heating and drying rates at 500 hPa along 22.5° N shows large positive heating and drying rates of the order of 16° C per day over the western trough region around 26 June. Following this event, low positive or negative values are observed over central India in July.The y-t diagram of vertical velocity at 500 hPa shows strong subsidence near the foot hills of Himalayas during the season. This has affected the formation of depressions or storms over Bay of Bengal and Arabian Sea. Adiabatic and diabatic heating as well as drying in the troposphere has led to the break-like situation over India in July 2002 and weaker monsoon circulation during August and September. The analysis has brought out the impact of northern hemispheric mid-latitude circulation on intra-seasonal variability of southwest monsoon 2002 more clearly. 

Frontal variability and its impact on chlorophyll in the Arabian Sea

2020 ◽  
Author(s):  
Yuntao Wang ◽  
Wentao Ma ◽  
Feng Zhou ◽  
Chai Fei
Keyword(s):  
Arabian Sea ◽  
Coastal Upwelling ◽  
Cold Water ◽  
Southwest Monsoon ◽  
Ocean Dynamics ◽  
Ekman Transport ◽  
Spatial And Temporal Variability ◽  
Anomalous Field ◽  
The North ◽  
The Impact

&lt;p&gt;Sixteen years satellite observations are used to investigate the frontogenesis, frontal variability and its impact on chlorophyll in the Arabian Sea. Large frontal probability (FP) and high chlorophyll mainly happens near the coast, e.g., near Somalia and Oman, and its value generally decreases with offshore distance. An Empirical Orthogonal Function (EOF) is used to disentangle the spatial and temporal variability of front and chlorophyll. Prominent seasonal cycle of frontal activities is identified, peaking in summer when southwest wind prevails. The seasonality for chlorophyll is same with wind and front near Somalia, which largely impacted by monsoon. During summer, the southwest monsoon drives offshore Ekman transport and induces coastal upwelling. It transports subsurface cold water and nutrients to the surface layer, which generates fronts and enhances chlorophyll, respectively. The frontal activities can be used as an indicator to determine the chlorophyll level that high chlorophyll happens when frontal probability gets higher than 2%. At anomalous field, stronger wind can induce higher frontal activities and chlorophyll. The impact of wind on frontogenesis can extend 1,000km offshore and a simplified linear regression is applied to quantify their relationship. The variability of wind leads chlorophyll by lags increasing with distance, indicating a horizontal offshore transport of coastal water. In winter, the northeast wind is not upwelling favorable, thus the frontal activities and chlorophyll are greatly reduced off Somalia. During this period, large chlorophyll is found in the north off Oman because of mixing, thus its relationship with front is less pronounced. In the upwelling regions, fronts act as an intermedia process that connecting the wind forcing and responses of ecosystem. The frontal activities in Arabian Sea is fundamentally important to improve our understanding of monsoon related ocean dynamics.&lt;/p&gt;

Southwest Monsoon Circulation and Environments of Recent Planktonic Foraminifera in the Northwestern Arabian Sea

1992 ◽  
Vol 7 (6) ◽  
pp. 799-813 ◽  
Author(s):  
John C. Brock ◽  
Charles R. McClain ◽  
David M. Anderson ◽  
Warren L. Prell ◽  
William W. Hay
Keyword(s):  
Arabian Sea ◽  
Planktonic Foraminifera ◽  
Southwest Monsoon ◽  
Monsoon Circulation

scholarly journals The Impact of the Madden–Julian Oscillation on Cyclone Amphan (2020) and Southwest Monsoon Onset

2020 ◽  
Vol 12 (18) ◽  
pp. 3011
Author(s):  
Heather L. Roman-Stork ◽  
Bulusu Subrahmanyam
Keyword(s):  
Bay Of Bengal ◽  
Heat Content ◽  
Southwest Monsoon ◽  
Ocean Model ◽  
Madden Julian Oscillation ◽  
Atmospheric Conditions ◽  
Kelvin Wave ◽  
Upper Ocean Heat Content ◽  
Southeastern Arabian Sea ◽  
The Impact

Cyclone Amphan was an exceptionally strong tropical cyclone in the Bay of Bengal that achieved a minimum central pressure of 907 mb during its active period in May 2020. In this study, we analyzed the oceanic and surface atmospheric conditions leading up to cyclogenesis, the impact of this storm on the Bay of Bengal, and how the processes that led to cyclogenesis, such as the Madden–Julian Oscillation (MJO) and Amphan itself, in turn impacted southwest monsoon preconditioning and onset. To accomplish this, we took a multiparameter approach using a combination of near real time satellite observations, ocean model forecasts, and reanalysis to better understand the processes involved. We found that the arrival of a second downwelling Kelvin wave in the equatorial Bay of Bengal, coupled with elevated upper ocean heat content and the positioning of the convective phase of the MJO, helped to create the conditions necessary for cyclogenesis, where the northward-propagating branch of the MJO acted as a trigger for cyclogenesis. This same MJO event, in conjunction with Amphan, heavily contributed atmospheric moisture to the southeastern Arabian Sea and established low-level westerlies that allowed for the southwest monsoon to climatologically onset on June 1.

scholarly journals Ball screw unit precise modelling with dynamics of loads and moving heat sources taken into account

2019 ◽  
Vol 19 (4) ◽  
pp. 27-41
Author(s):  
Jerzy JEDRZEJEWSKI ◽  
Zbigniew KOWAL ◽  
Wojciech KWASNY ◽  
Zdzislaw WINIARSKI
Keyword(s):  
Heat Source ◽  
Thermal Behaviour ◽  
Ball Screw ◽  
Fe Model ◽  
Heat Sources ◽  
Positioning Error ◽  
Positioning Precision ◽  
Head Positioning ◽  
Work Cycle ◽  
The Impact

This paper deals with the precision modelling of the ball screw unit’s thermal behaviour in the turning centre and its impact on the tool head positioning error. The error components along controllable axes X and Z are described in detail using an FE model integrating the changes in thermal and force loads and deformations occurring during the motion of the nut as a heat source. The impact of the nut work cycle on the thermal deformations of the ball screw and the displacements of the slideways and the screw points along both the axes and on carriage positioning precision is demonstrated.

scholarly journals Remote-Sensing-Based Estimation of Surface Nitrate and Its Variability in the Southern Peninsular Indian Waters

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
R. K. Sarangi
Keyword(s):  
Indian Ocean ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Nitrate Concentration ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Northern Indian Ocean ◽  
Noaa Avhrr ◽  
Nitrate Concentrations ◽  
High Nitrate Concentration

A relationship between sea surface temperature (SST) and surface nitrate concentrations has been obtained for the first time based on in situ datasets retrieved from U.S. JGOFS (1991–96) and Indian cruises (2000–2006) in the Arabian Sea, Bay of Bengal and Indian Ocean region around the southern Indian tip. The dataset includes 1537 points. A sigmoid relationship obtained with value 0.912. NOAA-AVHRR pathfinder satellite monthly averaged SST data retrieved from the PODAAC/JPL/NASA archive during July 1999–June 2004. The datasets imported in the ERDAS-Imagine software and SST images generated on monthly and seasonal scales, for latitudes 5–12°N and longitudes 75–85°E. The ocean surface nitrate images retrieved based on the established sigmoid relationship with SST. The nitrate concentrations ranged between 0.01–3.0 μM and categorized into five ranges. The significant seasonal upwelling zone around the southwest coast of India (Kerala coast, Latitude 80.10–9.30°N and Longitude 75.60–76.20°E) was identified during July–September 1999–2004 with very high nitrate concentration (~1.00 μM). Low nitrate and nitrate-depleted zones observed during summer (March–May). In the Arabian Sea and northern Indian Ocean, high nitrate concentration (~0.50 μM) observed during the southwest monsoon (SWM), whereas the Bay of Bengal was marked with high nitrate (~0.50 μM) during the northeast monsoon (NEM). SST was high (~29°C) in the Bay of Bengal and low (~26°C) in the Arabian Sea and northern Indian Ocean during SWM and vice versa during the NEM. There is a clear inverse relationship between nitrate and SST in the study area during July 1999–June 2004.

scholarly journals The effect of seasonally and spatially varying chlorophyll on Bay of Bengal surface ocean properties and the South Asian monsoon

2020 ◽  
Vol 1 (2) ◽  
pp. 635-655
Author(s):  
Jack Giddings ◽  
Adrian J. Matthews ◽  
Nicholas P. Klingaman ◽  
Karen J. Heywood ◽  
Manoj Joshi ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Mixed Layer ◽  
Bay Of Bengal ◽  
General Circulation ◽  
Southwest Monsoon ◽  
Radiative Heating ◽  
Radiation Absorption ◽  
Upper Ocean ◽  
Monsoon Circulation ◽  
Spatially Varying

Abstract. Chlorophyll absorbs solar radiation in the upper ocean, increasing the mixed layer radiative heating and sea surface temperatures (SST). Although the influence of chlorophyll distributions in the Arabian Sea on the southwest monsoon has been demonstrated, there is a current knowledge gap regarding how chlorophyll distributions in the Bay of Bengal influence the southwest monsoon. The solar absorption caused by chlorophyll can be parameterized as an optical parameter, h2, which expresses the scale depth of the absorption of blue light. Seasonally and spatially varying h2 fields in the Bay of Bengal were imposed in a 30-year simulation using an atmospheric general circulation model coupled to a mixed layer thermodynamic ocean model in order to investigate the effect of chlorophyll distributions on regional SST, the southwest monsoon circulation, and precipitation. There are both direct local upper-ocean effects, through changes in solar radiation absorption, and indirect remote atmospheric responses. The depth of the mixed layer relative to the perturbed solar penetration depths modulates the response of the SST to chlorophyll. The largest SST response of 0.5 ∘C to chlorophyll forcing occurs in coastal regions, where chlorophyll concentrations are high (> 1 mg m−3), and when climatological mixed layer depths shoal during the inter-monsoon periods. Precipitation increases significantly (by up to 3 mm d−1) across coastal Myanmar during the southwest monsoon onset and over northeast India and Bangladesh during the Autumn inter-monsoon period, decreasing model biases.

scholarly journals Latitudinal distribution of water vapour over the Arabian Sea and Bay of Bengal using Bhaskara-II SAMIR data

MAUSAM ◽  
2021 ◽  
Vol 43 (4) ◽  
pp. 385-394
Author(s):  
P.N. PATHAK ◽  
N. GAUTAM
Keyword(s):  
Water Vapour ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Latitudinal Gradient ◽  
Southwest Monsoon ◽  
Climatological Data ◽  
Latitude Range ◽  
Uniform Value ◽  
Northern Winter ◽  
Indian Seas

The main purpose of the present work is to establish the reliability of the SAMIR-derived water vapour (WV) data over the Arabian Sea and the Bay of Bengal for the entire 18-month from January 1982 to June 1983 period of the in-orbit operation of the SAMIR system. The average latitudinal distributions of WV over the Arabian Sea and Bay of Bengal for different months, derived from the SAMJR data were found to be broadly consistent with the climatological data on WV from the coastal and island radiosonde stations.   A significant latitudinal gradient in WV has been found during the northern winter months (Dec-Feb) with the highest value of 4-5 gm/cm2 near the equator and thc lowest value of about 2 gm/cm2 at about 20oN over the Indian seas. This gradient gradually decreases during the subsequent months and almost vanishes during the southwest monsoon months (Jun-Sep) when the WV has nearly uniform value of 4-5 gm/cm2 in the entire latitude range from the equator to 20oN over the Indian seas. Finally, it has been found that WV values over the Bay of Bengal are generally higher than those over the Arabian Sea at co-latitudinal positions. The implications of this result are discussed in the light of other considerations.

scholarly journals Emission Controls Using Different Temperatures of Combustion Air

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Radovan Nosek ◽  
Michal Holubčík ◽  
Štefan Papučík
Keyword(s):  
Heat Source ◽  
Air Temperature ◽  
Combustion Process ◽  
Maximum Efficiency ◽  
Heat Sources ◽  
Energy Transformation ◽  
Performance And Emission ◽  
Emission Controls ◽  
Different Temperatures ◽  
The Impact

The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass.

scholarly journals A Climatology of Arabian Sea Cyclonic Storms

2011 ◽  
Vol 24 (1) ◽  
pp. 140-158 ◽  
Author(s):  
Amato T. Evan ◽  
Suzana J. Camargo
Keyword(s):  
Bay Of Bengal ◽  
Environmental Conditions ◽  
Arabian Sea ◽  
Large Scale ◽  
Late Onset ◽  
Southwest Monsoon ◽  
Reanalysis Data ◽  
Tropical Cyclogenesis ◽  
Storm Frequency ◽  
Cyclonic Storms

Abstract On average 1–2 tropical cyclones form over the Arabian Sea each year, and few of these storms are intense enough to be classified as very severe or super cyclonic storms. As such, few studies have explicitly identified the seasonal to interannual changes in environmental conditions that are associated with Arabian Sea tropical cyclogenesis. However, over the last 30 yr several intense Arabian storms did form and make landfall, with large impacts, which motivates this new study of the basin. The conclusions of earlier studies are visited by utilizing modern observational and reanalysis data to identify the large-scale features associated with Arabian tropical cyclone variability on seasonal time scales. Then year-to-year changes in environmental conditions that are related to interannual variability in Arabian storms during the pre- and postmonsoon periods are elucidated. The analysis of the relationship between large-scale environmental variables and seasonal storm frequency supports conclusions from work completed more than 40 yr prior. Investigation of the year-to-year changes in premonsoon storm frequency suggests that May (June) storms are associated with an early (late) onset of the southwest monsoon. The findings also demonstrate that November cyclones (the month when the majority of postmonsoon cyclogenesis occurs) primarily form during periods when the Bay of Bengal experiences a broad region of high sea level pressure, implying that November storms form in either the Arabian Sea or the Bay of Bengal but not in both during the same year. Finally, the analysis of changes in a genesis potential index suggests that long-term variability in the potential for a storm to form is dictated by changes in midlevel moisture.

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