what causes the rainfall during summer monsoons in japan
Climate of Asia A large annual rainfall minimum, composed primarily of deserts, stretches from the Gobi Desert in Mongolia west-southwest through the Taklamakan Desert in Western China, the Thar Desert in Western India and Iranian Plateau into the Arabian Desert in the Arabian Peninsula. Rainfall around the continent is favored across its southern portion from Eastern India and Northeast India across the Philippines, Indochina, Malay Peninsula, Malay Archipelago and Southern China into Korean Peninsula Taiwan and Japan due to the Monsoon advecting moisture primarily from the Indian Ocean into the region.[3] The monsoon trough can reach as far north as the 40th parallel in East Asia during August before moving southward thereafter. Its poleward progression is accelerated by the onset of the summer monsoon which is characterized by the development of lower air pressure (a thermal low) over the warmest part of Asia.[4][5][6] Cherrapunji, situated on the southern slopes of the Eastern Himalaya in Shillong, India is one of the wettest places on Earth, with an average annual rainfall of 11,430 mm (450 in). The highest recorded rainfall in a single year was 22,987 mm (904.9 in) in 1861. The 38-year average at Mawsynram, Meghalaya, India is 11,873 mm (467.4 in).[7] Lower rainfall maxima are found around Turkey and central Russia.
Low-pressure area Thermal lows form due to localized heating caused by greater sunshine over deserts and other land masses. Since localized areas of warm air are less dense than their surroundings, this warmer air rises, which lowers atmospheric pressure near that portion of the Earth's surface. Large-scale thermal lows over continents help drive monsoon circulations. Low-pressure areas can also form due to organized thunderstorm activity over warm water. When this occurs over the tropics in concert with the Intertropical Convergence Zone, it is known as a monsoon trough. Monsoon troughs reach their northerly extent in August and their southerly extent in February. When a convective low acquires a well-hot circulation in the tropics it is termed a tropical cyclone. Tropical cyclones can form during any month of the year globally, but can occur in either the northern or southern hemisphere during November.