scholarly journals Probability studies of rainfall and crop production in coastal Tamil Nadu

MAUSAM ◽  
2022 ◽  
Vol 46 (3) ◽  
pp. 263-274
Author(s):  
N. CHATTOPADHYAY ◽  
G. S. GANESAN
Keyword(s):  
Tamil Nadu ◽  
Crop Production ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Weekly Basis ◽  
Monthly Basis ◽  
Dry Spells ◽  
Hot Weather ◽  
Wet Spells

Studies are made of the probability of Occurrence of annual and seasonal rainfall, wet and dry spells on monthly basis throughout the year and on weekly basis during the northeast monsoon season for various stations in coastal Tamil Nadu. It has been observed that amount of rainfall received is more in the stations north of Alangudi and north of Tondi in the northeast and southwest monsoon seasons respectively at all the probability levels. However, the quantum of rainfall is more in stations south of Adiramapattinam during the hot weather period. Number of wet spells are more from July to September in the stations of north costal Tamil Nadu. During the northeast monsoon season also wet weeks are mainly confined to the stations of north coastal Tamil Nadu. Analysis of production figures of some rainfed crops shows more productivity (k8I1\a) in north than in south coastal Tamil Nadu.  

scholarly journals Rainfall Profile of Cauvery Delta Zone of Tamil Nadu

2016 ◽  
Vol 11 (2) ◽  
pp. 524-530
Author(s):  
N. K Sathyamoorthy ◽  
R Jagannathan ◽  
A. P Ramaraj
Keyword(s):  
Tamil Nadu ◽  
Southwest Monsoon ◽  
Cold Weather ◽  
Northeast Monsoon ◽  
Water Crisis ◽  
Canal Irrigation ◽  
Increasing Trend ◽  
Hot Weather ◽  
Cauvery Delta ◽  
Normal Rainfall

Thanjavur and Nagapattinam districts of Cauvery Delta Zone (CDZ) depend on canal irrigation for agriculture and are subjected to the vagaries of monsoon. This creates water crisis and affects agriculture of the region considered as rice bowl of Tamil Nadu. This necessitated the study of rainfall to plan and mitigate water scarcity. Rainfall data from Adhirampattinam, Aduthurai stations of Thanjavur district (Inland) and Nagapattinam station (Coastal area of Nagapattinam district) were utilized for the study. Normal rainfall of CDZ is 956 mm; Nagapattinam receives highest (1350 mm) and aduthurai (994 mm) recorded lowest. November is the wettest month for all locations while driest month differs among locations. Northeast monsoon (NEM) was considered as stable monsoon for CDZ as could be seen from the seasonal mean of 641 mm, 620 mm and 919 mm recorded by Adhirampattinam, Aduthurai and Nagapattinam, respectively. Trend analysis of seasons revealed that Adhirampattinam and Nagapattinam follow a decreasing trend for rainfall and rainydays during NEM and Southwest monsoon (SWM), with an increasing trend for Hot weather period (HWP) and Cold weather period (CWP). An interesting deviation is that Aduthurai recording an increasing trend for NEM while it followed same trend for HWP and SWM.

scholarly journals SPATIO-TEMPORAL ESTIMATION OF INTEGRATED WATER VAPOUR OVER THE MALAYSIAN PENINSULA DURING MONSOON SEASON

2017 ◽  
Vol XLII-4/W5 ◽  
pp. 165-175
Author(s):  
S. Salihin ◽  
T. A. Musa ◽  
Z. Mohd Radzi
Keyword(s):  
Water Vapour ◽  
Monsoon Season ◽  
Temporal Distribution ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Path Delay ◽  
Zenith Path Delay ◽  
Temporal Estimation ◽  
Integrated Water Vapour ◽  
Spatio Temporal

This paper provides the precise information on spatial-temporal distribution of water vapour that was retrieved from Zenith Path Delay (ZPD) which was estimated by Global Positioning System (GPS) processing over the Malaysian Peninsular. A time series analysis of these ZPD and Integrated Water Vapor (IWV) values was done to capture the characteristic on their seasonal variation during monsoon seasons. This study was found that the pattern and distribution of atmospheric water vapour over Malaysian Peninsular in whole four years periods were influenced by two inter-monsoon and two monsoon seasons which are First Inter-monsoon, Second Inter-monsoon, Southwest monsoon and Northeast monsoon.

scholarly journals NGHIÊN CỨU XU THẾ BIẾN ĐỘNG TRƯỜNG NHIỆT ĐỘ BỀ MẶT BIỂN VÀ ẢNH HƯỞNG CỦA ENSO ĐẾN VÙNG BIỂN TÂY NAM VIỆT NAM SỬ DỤNG DỮ LIỆU VIỄN THÁM VÀ GIS

2020 ◽  
Vol 20 (2) ◽  
pp. 129-141
Author(s):  
Tran Anh Tuan ◽  
Vu Hai Dang ◽  
Pham Viet Hong ◽  
Do Ngoc Thuc ◽  
Nguyen Thuy Linh ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Monsoon Season ◽  
Linear Regression Analysis ◽  
Southwest Monsoon ◽  
Sea Surface ◽  
Northeast Monsoon ◽  
Temperature Trends ◽  
Sea Surface Temperature Anomalies ◽  
Southwest Monsoon Season

In this article, the sea surface temperature trends and the influence of ENSO on the southwest sea of Vietnam were analyzed using the continuous satellite-acquired data sequence of SST in the period of 2002–2018. GIS and average statistical methods were applied to calculate the average monthly and seasonal sea surface temperature, the seasonal sea surface temperature anomalies for each year and for the whole study period. Subsequently, the changing trends of sea surface temperature in the northeast and southwest monsoon seasons were estimated using linear regression analysis. Research results indicated that the sea surface temperature changed significantly throughout the calendar year, in which the maximum and minimum sea surface temperature are 31oC in May and 26oC in January respectively. Sea surface temperature trends range from 0oC/year to 0.05oC/year during the Northeast monsoon season and from 0.025oC/year to 0.055oC/year during the southwest monsoon season. Results based on the Oceanic Niño Index (ONI) analysis also show that the sea surface temperature in the study area and adjacent areas is strongly influenced and significantly fluctuates during El Niño and La Niña episodes.

scholarly journals Blue whales off the Southern coast of Sri Lanka during the Southwest Monsoon Season

2020 ◽  
Vol 21 (1) ◽  
pp. 1-7
Author(s):  
Grace Russell ◽  
Marcus Bridge ◽  
Maja Nimak-Wood
Keyword(s):  
Sri Lanka ◽  
Monsoon Season ◽  
Weather Conditions ◽  
Southwest Monsoon ◽  
Lower Latitude ◽  
Northeast Monsoon ◽  
Southern Coast ◽  
Northern India ◽  
Blue Whales ◽  
Southwest Monsoon Season

Observations of 37 individual blue whales (Balaenoptera musculus) were recorded off the southern coast of Sri Lanka during the Southwest Monsoon Season (SWM). Sightings were made during a scientific geophysical survey campaign conducted in July and August 2017. Whilst blue whales are regularly recorded on the continental slope of southern Sri Lanka during the Northeast Monsoon Season (NEM) (December - March) and during the two inter-monsoonal periods (March - April and September - October), limited data is available for the SWM (May - September) mostly due to unfavourable weather conditions and very little survey effort. In the northern hemisphere blue whales undertake seasonal migrations from higher latitude feeding grounds to lower latitude breeding and wintering areas. However it has been suggested that a population of blue whales in the Northern India Ocean (NIO) remains in lower latitudes year round taking advantage of the rich upwelling areas off Somalia, southwest Arabia and western Sri Lanka. Data from this study nevertheless support a theory that a certain number of individuals remain off the southern coast off Sri Lanka during the SWM, suggesting that the productivity in this region is sufficient to support their year-round presence. This study therefore fills a knowledge gap regarding the presence and movement of blue whales in the NIO highlighting the importance of data obtained from platforms of opportunity.

scholarly journals Spatial variation of clouding / rainfall over southeast Indian peninsula and adjoining Bay of Bengal associated with active and dry spells of northeast monsoon as derived from INSAT OLR data

MAUSAM ◽  
2021 ◽  
Vol 67 (3) ◽  
pp. 559-570
Author(s):  
B. AMUDHA ◽  
Y. E. A. RAJ ◽  
R. ASOKAN
Keyword(s):  
Spatial Variation ◽  
Tamil Nadu ◽  
Active Phase ◽  
Wave Radiation ◽  
Northeast Monsoon ◽  
Peninsular India ◽  
North East ◽  
The North ◽  
Northern Latitudes ◽  
Dry Spells

South Peninsular India (SPI) benefits largely from the rainfall (RF) realised during the North East Monsoon (NEM) season that prevails from October to December spilling over to January in some of the years.  Salient aspects of clouding / RF over SPI associated with 13 NEM seasons from 2000-01 to 2012-13 have been analysed using estimates of Outgoing Long wave Radiation (OLR) at 1° × 1° resolution derived from the radiance observations in the infra-red channel onboard the geostationary operational Indian satellite (INSAT) radiometers. OLR is considered as a proxy indicator for convective activity with the value of 230 Wm-2  as the threshold for RF occurrence. Year-to-year mean OLR patterns of the NEM season along with the latitudinal and longitudinal variabilities were analysed for dry, light and active phases of NEM. Based on rigorous analysis of INSAT OLR data for the above 13 years, it has been shown that during the active phase of NEM, Coastal Tamil Nadu (CTN) receives more RF while over BoB the RF is lower and decreases sharply over interior Tamil Nadu. This is a reiteration of a similar result from an earlier study based on 3 years (1996-98) OLR data from polar orbiting NOAA satellites. The spatial variation in OLR over the latitudes of 10.5, 12.5 and 14.5° N along  the longitudes of 75.5-85.5° E  has revealed the feature that  north of 10.5° N, values of OLR are higher with decrease in RF from south to north.  During dry phase of NEM in December and January, higher OLR is observed over northern latitudes of BoB than southern latitudes. It has been comprehended that in the southern latitudes of BoB, where higher sea surface temperatures (SST) are prevalent, more moisture is generated and pumped in to upper levels of the atmosphere leading to lower values of OLR compared to northern latitudes.  

scholarly journals Inter and intra-seasonal, variation of thermodynamic parameters of the atmosphere over coastal Tamilnadu during northeast monsoon

MAUSAM ◽  
2021 ◽  
Vol 47 (3) ◽  
pp. 259-268
Author(s):  
Y.E. A. RAJ
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Monsoon Season ◽  
Moisture Flux ◽  
Liquid Water Content ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Thermodynamic Structure ◽  
Clear Sign ◽  
Analysis Of Variation

The thermodynamic structure of the atmosphere over coastal Tamilnadu during the northeast monsoon season has been studied in detail based on the daily 0000 UTC upper air data between 1000  and 500 hPa levels of Madras for October-January for the l0 year period 1976-77 to 1985-86. Normal upper  air soundings have been computed for dry and wet spells of northeast monsoon and for the brief period of southwest monsoon prior to northeast monsoon onset. The moisture flux crossing  Madras and the liquid  water content over Madras have been computed for various categories of monsoon activity. It has been shown that the onset of easterlies over Madras is accompanied by a cooling of 1C of the atmosphere over Madras at all levels upto 500 hPa. An east to west moisture flux of 21.1 x 108 metric tons per day across one degree wall over Madras has been found to cross coast during typical wet spell of northeast monsoon. The moisture flux crossing coast for good northeast monsoon and also the normal flux computed for the period of study compared fairly well with the moisture flux crossing west coast during southwest monsoon obtained in various other studies. The energy of an air column over coastal Tamilnadu was found to decrease subsequent to the onset of northeast monsoon. Analysis of variation of liquid water content revealed that even during deficit rainfall years there was considereable amount of low level moisture in  the atmosphere. Neither during dryspells of northeast monsoon nor after its retreat was there any clear sign of spreading of continental air mass over coastal Tamilnadu.  

scholarly journals Simulation of the Hydrodynamic Field in Nhat Le Estuary, Quang Binh Province

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Nguyen Xuan Loc ◽  
Dang Dinh Thuc ◽  
Trang Vinh Quang
Keyword(s):  
River Flow ◽  
Monsoon Season ◽  
Maximum Flow ◽  
Research Problem ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Actual Measurement ◽  
S Waves ◽  
Hydrodynamic Field ◽  
The Waves

Hydrodynamic field is the primary research problem of all studies on coastal estuarine areas. Over the years, there have been many studies on Nhat Le estuary's region (Quang Binh). Still, these studies have not focused on simulating the characteristics of the hydrodynamics of this area. This study will present the ability to apply a mathematical model to simulate hydrodynamic fields for the region of Nhat Le estuary and Quang Binh sea by constructing the MIKE 21 model set based on the actual measurement database by the Center for Environmental Fluid Dynamics implemented in 2018. Through the calculation scenarios under different conditions, the longshore current mainly consists of Southeast - Northwest (especially with NE waves, the current direction is Northwest - Southeast) with current speed mostly in the range of 0.1 - 0.4 m/s. In estuarine areas, river flows have complicated developments, including many component flows. In the dry season, the river flow is not strong and is dominated by changes in the tide phase, withdrawal in a day. There are days of high flood flow in the flood season, overwhelming the tidal currents; the maximum flow velocity at the door can reach more than 6 m/s. Waves in the southwest monsoon season are relatively small, about 0.25 - 0.6 m; while the waves in the Northeast monsoon season are quite large and very strong during the storm, but when the depth is about -3 to -4 m, the wave height decreases sharply, spreading to the door. In particular, when there are floods in the river, the waves that propagate through this depth will almost calm.

scholarly journals Contrasting movement of wind based equatorial trough and equatorial cloud zone over Indian southern peninsula and adjoining Bay of Bengal during the onset phase of northeast monsoon

MAUSAM ◽  
2021 ◽  
Vol 58 (1) ◽  
pp. 33-48
Author(s):  
Y. E. A. RAJ ◽  
R. ASOKAN ◽  
P. V. REVIKUMAR
Keyword(s):  
Bay Of Bengal ◽  
Tamil Nadu ◽  
Southwest Monsoon ◽  
Monsoon Onset ◽  
Northeast Monsoon ◽  
Peninsular India ◽  
Zonal Winds ◽  
The North ◽  
Latitudinal Position ◽  
Onset Phase

ABSTRACT. The northeast monsoon sets in over southern parts of peninsular India after the retreat of southwest monsoon and in association with the southward movement of equatorial trough. The INSAT satellite imageries scrutinised during the past several years revealed that the cloud bands at the time of northeast monsoon onset moved from south Bay into the southern peninsula, a feature that contrasts with the north to south movement of the equatorial trough. The paper investigates this aspect based on a dataset of lower level upper winds of the peninsula, rainfall data and INSAT OLR data for the 20 year period 1981–2000. The super epoch profiles of zonal winds, latitudinal position of equatorial trough with reference to northeast monsoon onset dates have been derived and studied. The region with OLR values less than 230 W/m2 was defined as the equatorial cloud zone and the movement of northern limit of ECZ was studied based on the normal pentad OLR data and also the superposed epoch profiles. From these analysis it has been established that at the time of northeast monsoon onset, the wind based equatorial trough moves south of Comorin whereas the cloud zone in the Bay of Bengal moves from south to north. Reasons for the occurrence of such a contrasting feature have been ascribed to features such as decreasing strength of lower level easterlies from north to south over coastal Tamil Nadu, reversal of temperature gradient between Chennai and Thiruvananthapuram at the time of onset and the dynamics of 40-day oscillation. The northeast monsoon activity over coastal Tamil Nadu has been found to be negatively correlated with the low level zonal winds over the coast, the degree of relation decreasing from north to south and also from October to December. Based on the results derived in the study and also the other known features of northeast monsoon a thematic model of northeast monsoon onset listing the events that precede and succeed the onset has been postulated.

scholarly journals Simulation of spatial variation of plankton communities in the South Central Vietnam sea by ROMS model

2019 ◽  
Vol 19 (3) ◽  
pp. 371-384
Author(s):  
Vu Thi Vui
Keyword(s):  
Monsoon Season ◽  
Southwest Monsoon ◽  
Ocean Modeling ◽  
Northeast Monsoon ◽  
The South ◽  
Regional Ocean Modeling System ◽  
Roms Model ◽  
South Central ◽  
Central Vietnam ◽  
Plankton Communities

This study preliminarily applies the Regional Ocean Modeling System (ROMS) in the two major monsoon seasons (Northeast and Southwest monsoons) for the South Central Vietnam sea (9–14.5oN, 105–112oE), in which the hydrodynamic and ecological modules are coupled. The results show that the plankton only develop in 200 m water on the top, concentrated mainly in the 0–70 m layer and in maximum biomass of 15–40 m layer. In the Northeast monsoon season, the plankton are concentrated mainly in the northern part and open seas of the area, while in the Southwest monsoon season, they are concentrated in the upwelling and adjacent southern areas. These results correctly reflect the basic law of the development of plankton communities in the sea area.

scholarly journals Identifying and Using Suitable Oceanic Domains for Prediction of the Indian Monsoon Rainfall over Tamil Nadu

2021 ◽  
pp. 60-71
Author(s):  
G. Senbagavalli ◽  
N. K. Sathyamoorthy ◽  
Ga. Dheebakaran ◽  
Patil Santosh Ganapati ◽  
S. Kokilavani ◽  
...  
Keyword(s):  
Land Surface ◽  
Tamil Nadu ◽  
Monsoon Rainfall ◽  
Southwest Monsoon ◽  
Vital Role ◽  
Lead Times ◽  
Northeast Monsoon ◽  
Rainfall Prediction ◽  
Model Training ◽  
June July

Rainfall prediction are vital for agriculture which is one of the primary sectors greatly affected by climate variability and extremes. Agriculture plays a vital role in shaping the economy of India which is often affected by monsoon. Sea surface temperature (SST) plays a vital role in rainfall predictability over the land surface. A total of twelve different domains of oceanic influences of SST on monsoon rainfall over Tamil Nadu were selected for analysis. The SST of different lead times (February, March, April, and May for southwest monsoon (SWM) and June, July, August, and September for northeast monsoon (NEM) from the ERSSTv5 and ECMWF-SEAS5 model with the Canonical Correlation Analysis (CCA) were used in the Climate Predictability Tool (CPT) to identify the best predictor domains for the prediction of SWM and NEM rainfall over Tamil Nadu. The model training utilized the first 40 years (1981-2020) SST and rainfall data and prediction was done for the 2021 seasons. The results of the study revealed from Kendall tau goodness index and CCA score, the predictor domains comprised of a combination of oceanic domains, this were the Indian, Arabian, Bay of Bengal, and Pacific Oceans recorded the best CCA score and the goodness index. Is therefore recommended that, these domains which have the highest overall predictability can be used by the National meteorological services to early warning and monsoon rainfall information over Tamil Nadu.

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