Showing posts with label On Airs Water and Places. Show all posts
Showing posts with label On Airs Water and Places. Show all posts

Thursday, August 20, 2020

Windy

This amazing weather web page can show real time weather phenomenon. It shows atmospheric variables like wind speed, wind direction, wind gusts, rain, thunder, temperature, cloud cover, waves, air quality. It also shows forecasts of weather. Click on the yellow icon on right corner to visualize other weather variables. Visit the website here.

Local Winds of India


Map of Local winds India, Bordoli Chheerha, Mango Showers, Loo, Elephanta

Winds are atmospheric phenomenon attributable to difference in temperature and atmospheric pressure. They are significant component in establishing and regulating the weather and climate of a particular place as well as of global atmospheric phenomenon. Winds operate in different climatic scale in terms of its spatial and temporal aspects. They operate at planetary scale known as planetary winds; seasonal scale known as seasonal or periodic winds and regional scale known as local winds.

Local winds are winds with limited spatial and temporal scale as they effect a limited area and operates over a shorter period of time. There are many ways in which local winds effect the weather and climate of a particular places. Many local winds blow over different regions of India. The influence of these local winds ins not only limited to the climate and weather but also shapes the economic, cultural and social characteristics of the region. 

Local winds of India –

Aandhi, also known as Kali Aandhi are dust storms affecting the north western and central part of India. These storms are formed due to development of strong pressure gradient in the region late spring before monsoon season. Due to high surface heating in the dry Arabian Peninsula and the Thar desert, the loose soil/sand particles are transported through westerly winds to northern- central India (Middleton, 1986). These dust storms may become ferocious and cause destruction to life and property. The level of pollution in many urban centres like Delhi rises and the amount of suspended particles increase in air.


 
MODIS TERRA satellite image showing thick dust storms over India and Pakistan on June 9, 2003. Image courtesy - NASA


Loo are hot, dry winds blowing throughout the daytime in north and western India during the month of May and June. Loo winds are developed due to formation of the Monsoon Low Pressure Trough in northern India. To maintain balance, the hot dry winds of the surrounding areas move in causing formation of Loo. These dry winds are responsible for loss of life due to dehydration. However, it has some positive influences as it facilitates the process of separating the chaff from the grain. There is also decline in number of insect borne disease like malaria due to decrease in mosquito population.


Kalbaisakhi winds hitting Kolkata on 24 May, 2010. Photo Courtesy - Biswarup Ganguly, Wikipedia

 
Kalbaisakhi are the local winds affecting the eastern Indian states of West Bengal, Assam, Bangladesh and parts of Odisha and Bihar. It is known as different names in different states. Kal- Baisakhi means 'a fateful thing' in the month of Baisakh (Roy and Chatterji, 1929). In Assam, these are called Tea showers and Bordolichilla, and in Odisha as Bordoisila or Bardoli Chhera. These pre-monsoonal winds originate in the Chhota Nagpur plateau and blows eastwards under the influence of Westerlies. These warm winds when come in contact with moisture laden air and moves over elevated Himalayas in Assam and North Bengal, results in sudden rise in wind speed, lightning, thunder and hail and sometimes destructive tornadoes. It can cause destruction by uprooting trees and small houses. But then again, they sustain the pre-kharif crops like jute and paddy, and a large number of vegetables and fruits till summer season.

Mango showers are rains bearing local winds known with many different names as April rains, summer showers, coffee showers and cherry blossom showers. Names with cultivation prefix has been given to these light rains as it is beneficial for their growth. These pre-monsoonal winds are mainly experienced in south India prevailing along the coast of Kerala, Karnataka and parts of Tamil Nadu. They originate in the Bay of Bengal as the result of thunderstorm development.

Elephanta is a post monsoonal local wind impacting the Malabar coast of India. These are south easterly moisture laden winds which announces the beginning of dry season after monsoons and end of the rainy season. 

If you are more interested in winds; Earth, Windy, Windfinder are web based utilities which visualizes winds with wind direction, speed and other weather variables.

References - 

Middleton, N.J. (1986), A geography of dust storms in South‐West Asia. J. Climatol., 6: 183-196. doi:10.1002/joc.3370060207
Roy, S., Chatterji, G. Origin of Nor'westers. Nature 124, 481 (1929). https://doi.org/10.1038/124481a0










Wednesday, July 8, 2020

Monsoon Culture across the World.

What is Monsoon?

The word monsoon is derived from the Arabic mawsim (meaning “season”) and has come to mean a seasonal reversal of winds. In summer, the land get heated quickly as compared to water, resulting in general sea to land movement called onshore flow. Reverse happens in winters, as the land is cooler than the surrounding water bodies leading to general land-to-sea movement called offshore flow. The monsoon wind circulation also has a seasonal precipitation pattern with moist onshore flow in summer and dry offshore flow in winters.

Where is Monsoon found?

Monsoon are predominently associated with South Asian regions. However, it also occurs in east Asia, western Africa, northern part of Australia and Pacific coast of Central America.

https://cdn.pixabay.com/photo/2019/04/07/12/07/kerala-4109563_960_720.jpg
Monsoon in Kerala, India. Image by Ambady Sasi, Pixaby

Monsoonal Character and Culture across the World

Meghalaya, India (South Asian Monsoon)

The name literally mean the land of the clouds. It has two of the most wettest places in the world. Monsoon starts here by mid of May and continues up to the month of September and October. The monsoons increase the natural beauty of the State. The stretches of valleys and highland plateaus becomes misty and cloudy making it analogues to Scotland. The State has many lakes, waterfalls, brooks and gardens. The tallest plunge waterfall in India, the Nohkalikai Falls, goes through a spectacular makeover during the monsoons. The residents of the region are not afraid by heavy rainfall but have adapted their lives with knups and living root bridges.

These knups are used in areas around Meghalaya as an umbrella ...
Knups are traditional Khasi umbrellas, made from bamboo and banana leaves, to continue living their lives and earning livelihood during incessant rain and strong winds.



Living root bridges found in many villages of Meghalaya are great examples of sustainable local architecture.

https://upload.wikimedia.org/wikipedia/commons/thumb/5/51/Living_root_bridges%2C_Nongriat_village%2C_Meghalaya2.jpg/640px-Living_root_bridges%2C_Nongriat_village%2C_Meghalaya2.jpg
A double-decker living root bridge in Nongriat, Meghalaya. Photo courtesy Arshiya Urveeja Bose.

Kyushu Islands, Japan (East Asian Monsoon)

The climate of Japan is quite diverse ranging from temperate climate in northern Island to humid, tropical conditions in southern parts. Kyushu Island lies in Southernmost island of Japan. The monsoonal season in Kyushu Islands in Japan usually starts from end of May or start of June to mid July. The weather during the rainy season is unstable and unpredictable.
The Japanese word for rainy season is tsuyu, literally “plum rain” (梅雨), as it coincides with the season of plums ripening in Japan.  Another benefit of the rainy season is that many flowers bloom during this time. One of them is ajisai (hydrangea), which is a symbol of Japan's rainy season. A variety of irises also blooms during this season and can be seen on view in many gardens and parks.
https://cdn.pixabay.com/photo/2018/06/07/08/56/hydrangea-3459661_960_720.jpg

Hydrangea, the flower of the Japanese rainy season. Image courtesy -Takuyo (Pixabay)

The rainy season is considered as a gloomy time in Japan, that's why this period is generally avoided for tourism. In the urban life like city of  Fukuoka, umbrella become a unavoidable companion. There are also many indoor activities to keep people occupied in gloomy tsuyu season. Rain, mudslide and floods also affect the life of people during heavy rainfall during monsoons.

Darwin, North Australia (Australian Monsoon)

Summer monsoon in Darwin, Australia is different from rest of the world. The region receives its major rainfall through monsoons from december to april. Thunderstorms and high relative humdity are common occurance in the season.
Monsoon play a major role in setting up the natural ecostystem of the place which is quite different to that of non-monsoonal southern regions. Extensive wetlands, natural savanna vegetation and native wildlife has assisted in establishing three national park and extensive parks and gardens in Darwin. Tourism is the major industry and employment sector in Darwin.
https://upload.wikimedia.org/wikipedia/commons/1/16/Kakadu_2411.jpg
Escarpment and wetlands in Kakadu national park, Darwin. Image courtesy - Tourism NT

Liberia, West Africa (African Monsoon)

Liberia lies in the south facing coast of western Africa. The monsoon season in Liberia starts from May and continues up to the month of October. The climate during monsoon season is humid but not so hot. Main vegetation in the coastal parts of the region is mangroves. As one moves towards the inner parts of the country, tropical forests are found. In more interior dry parts of the country, grassland are found. The climate of Liberia is much moderate and humid as compared to the interior hot dry Sahara region because of monsoon.

Ross (1919) has written about the monsoons and its effect on Liberia in his research -
The rains have an important influence on the life of the country in relation to travel, transportation, communication and food supply.


Native Architecture of Liberia, Adapted to heavy monsoons. (Ross,1919)

He further writes about the life of the natives and the foreigner settlers during monsoon -

The season of rains is probably the most pleasant one for Europeans. There are few days during that season when the feeling is one of "stickiness" and great oppression, but such days are not common. The daily temperature range is from 3° to 10° F. A fire in an open grate, if a grate has been built into a house, as is infrequently the case, is a rather happy thing; its genial effect is more in drying out the house than in directly furnishing warmth. The natives are often sufferers from cold on rainy days and sit around the little fires that kept eternally going within their mud-walled houses.

Arizona, United State of America (Central American Monsoon) -

The summer monsoon in Arizona, USA is from July to mid of September. The monsoons here are charactersied by high temperatures, high winds and thunderstorms accompanied by gustnadoes, dust storms and sometimes tornadoes. Visibility is reduced because of dust storms. 

https://cdn.pixabay.com/photo/2020/07/05/02/39/tucson-5371392_960_720.jpg
Dark Monsoonal clouds visible over Tuscon, Arizona. Image by Philip,Pixabay

Flash Flooding is also a common occurrence due to brief but heavy downpours. This can lead to dangerous circumstances and government has passed the Stupid Motorist Law, which may lead to charging the rescue cost from the motorist who has entered a flooded area of roadway.

Add your comments.

Reference

Ross, Emory. “The Climate of Liberia and Its Effect on Man.” Geographical Review, vol. 7, no. 6, 1919, pp. 387–402. JSTOR, www.jstor.org/stable/207671. Accessed 8 July 2020.