Explanation:   Factors Causing Rainfall Patterns Change:   Moisture and Drought Together:   An aspect of warming that influences rainfall is the drying of the land, which increases the frequency and intensity of dry periods and Droughts.An increase in moisture and the drying up together change the rainfall patterns in unpredictable ways. Hence, statement 1 is correct. Increased Snowfall in the Eurasian Region: Increased snowfall in the Eurasian region also impacts monsoon rainfall in NE India as the excessive snowfall in Eurasia causes cooling of the atmosphere of the region, which triggers events eventually leading to a weak summer monsoon season there. Hence, statement 2 is correct. Change in Pacific Decadal Oscillation (PDO): Sea surface temperatures over the subtropical Pacific Ocean, which vary in a cycle and each phase of which lasts a decade. The peak comes every 20 years and is known as the Pacific Decadal Oscillation (PDO).It may have an impact on the monsoon rainfall in NE. Hence, statement 3 is correct. Sunspot Epoch: During the monsoon, rainfall patterns in NE differed significantly from one Sunspot epoch to another, suggesting a differential intensification of the seasonal trough of low pressure over the country. Hence, statement 4 is correct. Hence, option (d) is the correct answer.

Explanation:

 

A recent study that looked at the rainfall pattern in the past 119 years found a decreasing trend at Cherrapunji (Meghalaya) and nearby areas.

The rainfall in Cherrapunji-Mawsynram is caused by the orography favouring a monsoon wind regime. Hence, statement 1 is correct.

The changes in the Indian Ocean temperature have a huge effect on the rainfall in the region. Increasing sea surface temperatures in the tropical Indian Ocean region was pointed out by the first climate change assessment report published by the Union Ministry of Earth Sciences in June 2020. Hence, statement 2 is correct.

Another reason for decline in rainfall in this region is that there is sizable deforestation in the region. The study saw the decrease in vegetation cover and increase in the areas of cropland mainly from the year 2006 onwards. Hence, statement 3 is correct.

Explanation:

Both the statements are correct.

Both El Nino and MJO are ocean-atmosphere interactions that occur in the equatorial region and influence a number of weather events worldwide, including the Indian monsoon. El Nino, the unusual warming of sea-surface Pacific waters off the South American coast, is a stationary system. The MJO, on the other hand, is a moving system of wind, cloud and pressure that brings rain as it circles around the equator. The journey of MJO goes through eight phases. When it is over the Indian Ocean during the Monsoon season, it brings good rainfall over the Indian subcontinent. On the other hand, when it witnesses a longer cycle and stays over the Pacific Ocean, MJO is bad for the Indian Monsoon.

Cloudburst is extreme precipitation, which lasts only for a short period of time and is extremely local in nature.

Cloudbursts usually occur in connection with a thunderstorm.

While there is a greater probability of cloudbursts occurring in the mountains and hilly areas, cloudbursts can also occur in plains.

There is two distinct systems of monsoons in Indian. Southwest Monsoons: It causes rainfall during the months of June to September. It burst in the first week of June in the coastal areas of Kerala, Karnataka, Goa, and Maharashtra while in the interior parts of the country, it may be delayed to the first week of July. It is responsible for the majority of rainfall in North as well as South India. It causes rainfall in Western Ghats, Western Coastal Plain, Gujarat region, Maharashtra coast, Central India, Chotanagpur plateau, North Eastern region and Gangetic plains.North-East or Winter Monsoon or Retreating Monsoon : It causes rainfall in the months of October to December. It is mainly responsible for rainfall on the eastern coast of Tamil Nadu and a small adjoining region. Hence, statement 1 is not correct. Northern India experiences a high daily and annual range of temperatures than Southern India. The northern part of India lies in the sub-tropical and temperate zone and the part lying south of the Tropic of Cancer falls in the tropical zone. The tropical zone being nearer to the equator experiences high temperatures throughout the year with a small daily and annual range. The area north of the Tropic of Cancer being away from the equator experiences an extreme climate with a high daily and annual range of temperature. Hence, statement 2 is correct.

Explanation:

Frontal rain and Cyclonic rain are same. Convection rain is when air on being heated, becomes light and rises up in convection currents.

Explanation:

Condensation is when water vapour transforms into water. Precipitation is when condensed particles grow enough in size so as to resist the gravity and hence fall down. Dew, frost, fog, mist, rime, smog and haze are phenomena resulting from condensation of water vapour. While, rainfall, snowfall, sleet and hailstorm are forms of precipitation.

Explanation:

Aerosols also can act as sites for chemical reactions to take place such as those that lead to the destruction of stratospheric ozone.During winter in the Polar Regions, aerosols grow to form polar stratospheric clouds. The large surface areas of these cloud particles provide sites for chemical reactions to take place.These reactions lead to the formation of large amounts of reactive chlorine and, ultimately, to the destruction of ozone in the stratosphere.Statement 1 and 3: Aerosols interact both directly and indirectly with the Earth’s radiation budget and climate. As a direct effect, the aerosols scatter sunlight directly back into space. This cools down the planet, so 3 is wrong. As an indirect effect, aerosols in the lower atmosphere can modify the size of cloud particles, changing how the clouds reflect and absorb sunlight, thereby affecting the Earth’s energy budget.

Explanation:

 

Madden Julian Oscillation (MJO):

The Madden Julian Oscillation (MJO) is one of the most important atmosphere-ocean coupled phenomena in the tropics, which has profound influence on the Indian Summer Monsoon.

The MJO can be defined as an eastward moving ‘pulse’ of clouds, rainfall, winds and pressure near the equator that typically recurs every 30 to 60 days. Hence, statement 1 is correct. The MJO is the leading mode of tropical intra-seasonal climate variability and is characterized by organization on a global spatial scale with a period typically ranging between 30-60 days.

When Madden Julian Oscillation is over Indian Ocean during Monsoon season, it brings good rainfall over the Indian subcontinent. Hence, statement 2 is correct. On the other hand, when it witnesses a longer cycle and stays over the Pacific Ocean, MJO brings bad news for the Indian Monsoon. It is linked with enhanced and suppressed rainfall activity in the tropics and is very important for the Indian monsoonal rainfall.

It has the following characteristics:

MJO is a massive weather event consisting of deep convection coupled with atmospheric circulation, moving slowly eastward over the Indian and Pacific Oceans.

MJO is an equatorial traveling pattern of anomalous rainfall that is planetary in scale.

Each cycle lasts approximately 30–60 days. Also known as the 30-60 day oscillation, 30-60 day wave, or intra-seasonal oscillation (ISO).The MJO involves variations in wind, sea surface temperature (SST), cloudiness, and rainfall. Based on the place of convective activity the period of MJO is divided into 1-8 phases with each phase roughly last for 7 to 8 days.

Since the MJO is the most important mode of tropical intra-seasonal variability with potentially important influences on monsoon activity in the Asian regions on extended range time scale (beyond 7 days to one month), the capability of statistical or numerical models in capturing MJO signal is very crucial in capturing the active/break cycle of monsoon.

Explanation:

Variability of Rainfall refers to the degree to which rainfall amounts vary across an area or through time. There are two types (or components) of rainfall variability:

Areal: The variation of rainfall amounts at various locations across a region for a specific time interval. (Time does not vary.) Example: Annual average precipitation Temporal: The variation of rainfall amounts at a given location across a time interval. (Area does not vary.)

The variability of rainfall is computed with the help of the following formula:

C.V. = (Standard Deviation/Mean)*100 ……(C.V. is the coefficient of variation) The values of the coefficient of variation show variability of rainfall in India.

Different regions in India experience different ranges of variability:

Variability less than 25 percent: Western coasts, Western Ghats, northeastern Peninsula, eastern plains of the Ganga, northeastern India, Uttarakhand and Himachal Pradesh and south-western part of Jammu and Kashmir. These areas have an annual rainfall of over 100 cm. Variability greater than 50 percent: Western part of Rajasthan, northern part of Jammu and Kashmir and interior parts of the Deccan plateau. These areas have an annual rainfall of less than 50 cm. Variability of 25-50 percent: Rest of India such as Western Gangetic Plains. These areas receive an annual rainfall between 50 -100 cm