Skip to main content

Winds

Wind Atmospheric motion characterized by direction and speed. The

direction of the wind is the direction from which the wind

approaches the station (Example Northerly wind – Wind

approaching the station from North)

Gales A gale is a very strong wind (34 to 47 knots)

Squall A sudden increase of wind speed by atleast 3 stages on the

Beaufort Scale, the speed rising to force 6 or more, and

lasting for atleast one minute is called a squall

Gust A rapid increase in the strength of the wind relative to the

mean strength at the time


 

Monsoon

"MONSOON" has originated from the Arabic word "MAUSIM" which

means season. It is most often applied to the seasonal reversals of the wind

direction along the shores of the Indian Ocean, especially in the Arabian Sea,

that blow from the southwest during one half of the year and from the

northeast during the other.

Onset & Advance of Monsoon

The guidelines to be followed for declaring the onset of monsoon over Kerala

and its further advance over the country are enlisted below:

Onset over Kerala

a) Rainfall

If after 10th May, 60% of the available 14 stations enlisted*, viz. Minicoy,

Amini,Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam,

Kochi, Thrissur, Kozhikode, Thalassery,Kannur, Kasargode and

Mangalore report rainfall of 2.5 mm or more for two consecutive days, the

onset over Kerala be declared on the 2nd day, provided the following

criteria are also in concurrence.

b) Wind field

Depth of westerlies should be maintained upto 600 hPa, in the box

equator to Lat. 10ºN and Long. 55ºE to 80ºE. The zonal wind speed over

the area bounded by Lat. 5-10ºN, Long. 70-80ºE should be of the order of

15 – 20 Kts. at 925 hPa. The source of data can be RSMC wind analysis/

satellite derived winds.

3. Outgoing Longwave Radiation (OLR)

INSAT derived OLR value should be below 200 wm-2 in the box confined

by Lat. 5-10ºN and Long. 70-75ºE.


 

Further Advance of Monsoon over the Country

a) Further advance be declared based on the occurrence of rainfall over

parts/sectors of the sub-divisions and maintaining the spatial continuity of

the northern limit of monsoon, further advance be declared.

The following auxiliary features may also be looked into:

b) Along the west coast, position of maximum cloud zone, as inferred from

the satellite imageries may be taken into account.

c) The satellite water vapour imageries may be monitored to assess the

extent of moisture incursion.

Northern Limit of Monsoon (NLM)

Southwest monsoon normally sets in over Kerala around 1st June. It

advances northwards, usually in surges, and covers the entire country

around 15th July. The NLM is the northern most limit of monsoon upto

which it has advanced on any given day.

Withdrawal of SW Monsoon

a) Withdrawal from extreme north-western parts of the country should not

be attempted before 1st September.

b) After 1st September:

The following major synoptic features should be considered for the first

withdrawal from the western parts of NW India.

i) Cessation of rainfall activity over the area for continuous 5 days.

ii) Establishment of anticyclone in the lower troposphere (850 hPa and

below)

iii) Considerable reduction in moisture content as inferred from satellite

water vapour imageries and tephigrams.

Further Withdrawal from the Country

i) Further withdrawal from the country may be declared, keeping the

spatial continuity, reduction in moisture as seen in the water vapour

imageries and prevalence of dry weather for 5 days.


 

ii) SW monsoon should be withdrawn from the southern peninsula and

hence from the entire country only after 1st October, when the circulation

pattern indicates a change over from the southwesterly wind regime.

Commencement of NE monsoon rains

i) Withdrawal of SW monsoon upto Lat. 15ºN.

ii) Onset of persistent surface easterlies over Tamil Nadu coast.

iii) Depth of easterlies upto 850 hPa over Tamil Nadu coast.

iv) Fairly widespread rainfall over coastal Tamil Nadu, south coastal Andhra

Pradesh and adjoining areas.


 

Criteria for Declaring Onset of Northeast Monsoon

For declaring onset of Northeast Monsoon following criteria may be

considered:

(1) Withdrawal of south west Monsoon upto 15º N.

(2) Onset of persistent surface easterlies over Tamil Nadu coast.

(3) Depth of easterlies upto 850 hpa over Tamil Nadu coast.

(4) Fairly widespread rainfall over the coastal Tamil Nadu and adjoining areas.

(5) Onset is not to be declared before 10th October even, if the conditions

described above exist.

Comments

Popular posts from this blog

UNIT 13 FEATURES OF 73rd AND 74th CONSTITUTIONAL AMENDMENT

Structure

13.0 Learning Outcome

13.1 Introduction

13.2 Initiatives towards Constitutional Status to Local Governance

13.2.1 Features of 73rd Constitutional Amendment

13.2.2 Features of 74th Constitutional Amendment

13.2.3 Decentralised Planning in Context of 73rd and 74th Constitutional Amendment Act

13.3 Initiatives after Economic Reforms

13.4 Functioning of PRIs in Various States after 73rd Amendment

13.5 Functioning of Local Governance after 73rd and 74th Constitutional Amendment: Observations

13.6 Conclusion

13.7 Key Concepts

13.8 References and Further Reading

13.9 Activities

13.0 LEARNING OUTCOME

After studying this Unit you should be able to:

• Identify the background of revitalisation of local governance;

• Understand the features of 73rd and 74th constitutional amendment;

• Discuss the initiatives after economic reforms; and

• Outlines the functioning of local governance in various states after the amendment.

13.1 INTRODUCTION

The revitalization of Pancha…

UNIT 1 CONCEPT, EVOLUTION AND SIGNIFICANCE OF DEMOCRATIC DECENTRALISATION

Structure

1.0 Learning outcome

1.1 Introduction

1.2 Concept of Democratic Decentralisation

1.3 Evolution of Democratic Decentralisation

1.4 Significance of Democratic Decentralisation

1.5 Democratic Decentralisation in India

1.6 Conclusion

1.7 Key concepts

1.8 References and Further Reading

1.9 Activities

1.0 LEARNING OUTCOME

After studying this unit, you should be able to:

• Understand the concept of Democratic Decentralization;

• Know the evolution and significance of Democratic Decentralization; and

• Describe the Democratic Decentralization pattern in India.

1.1 INTRODUCTION

The dawn of 21st century is marked by decentralized governance both as a strategy and philosophy of brining about reforms and changes in democracies. These changes led to such virtues of transparency, responsiveness and accountability and ensures good governance. Today decentralization and democracy are the most significant themes in the development discourse. In the present contex…

General Studies :: Indian Polity #1

Constitutional evolution under British ruleRegulating Act 1773beginning of British parliamentary control over the East India Companysubordination of the presidencies of Bombay and Madras to BengalGovernor of Bengal made Governal-Generalcouncil of Governor-General establishedSupreme Court established in CalcuttaPitt’s India Act 1784commercial and political activities of the Company separatedestablished a board of control over the CompanyCharter Act 1813trade monopoly of the Company abolishedmissionaries allowed to preach in IndiaCharter Act 1833Governor-General of Bengal becomes Governor-General of Indiafirst Governor-General Lord William Bentickends commercial activities of the CompanyCharter Act 1853legislative and executive functions of the Governor-General’s council separatedopen competition for Indian Civil Services establishedIndian Council Act 1861establishes legislative councils at the centre, presidencies and provincesGovernor-General’s executive council to have Indians as non…