Why are the currents off the coast of Somalia warm in winter?

Normally, ocean currents flowing from lower to higher latitudes are supposed to be warm, but the Somali Current breaks this routine and is a cold snap.

The Somali Current is a monsoon current, and its nature varies significantly with the prevailing winds, the northeast monsoon and the southwest monsoon. Winter is a warm snap and summer is a cold snap. In summer, the strong southwest monsoon prevails in the northern Indian Ocean, where the southwest monsoon is more stable and stronger than the northeast monsoon, often reaching 4 6 force winds, and the surface water flow rate is generally 130 160 cm s, sometimes up to 250 cm s.

As a result, the summer monsoon drives the surface water northeastward, and after the warm surface water has flowed away, colder, less salinity water masses rise from the deep-water basins of the adjacent peninsula to compensate for the surface water, resulting in lower water temperatures off the coast of Somalia than in the nearby seas2 3. Hence the cold snap. In addition, during this period, the direct sunlight gradually moved northward to near the Tropic of Capricorn, and the solar radiation in the Arabian Sea and its two sides increased, becoming one of the hot regions in the world, with the temperature on land often reaching more than 30, and the "baking" of the surrounding dry and hot land made the surface water temperature of the Arabian Sea as high as 28 or more, which was about 5 higher than the water temperature of the eastern coastal waters of the Somali Peninsula.

This is one of the reasons why the Somali Current has a cold nature.

I think there are three reasons why the northeast monsoon prevails in the north Indian Ocean in winter: first, the low latitude of the northern Indian Ocean sea area, the dry coastal climate, less cloud cover, strong solar radiation, and relatively high temperatures throughout the year, which obtains more solar radiation energy -- this is the main reason for the high sea temperature; Second, the coast is mostly a dry tropical desert climate, with no inflow of large rivers, and the sea water is less diluted - so the salinity is higher; Third, although the sea area is open to the south, because it is located near the equator and the formation of circulation, the seawater here is less likely to fully communicate with the seawater of the southern ocean, so it can maintain the characteristics of high temperature and high salinity of the seawater near the equator.

1. The northeast monsoon prevails in the northern Indian Ocean in winter. 2. The main supply of seawater flows through the Arabian desert area. The region is located in a low-latitude desert area, with high temperatures all year round and no rivers flowing into the sea, and high salinity.

The nature of the current should be determined by comparing the temperature and salinity of the flowing seawater with that of the original local seawater, rather than judging the direction of the current.

SomaliaThe causes of the warm current and the cold current in Somalia are as follows:

1. The cause of cold snaps in summer.

In summer, the surface waters of the Arabian Sea are blown offshore by the southwest monsoon, while the waters off the nearby East African coast flow to compensate for the loss of seawater, creating an up-compensating current. According to the surface sea temperature of the ocean.

The law of vertical decline can be carefully understood, and the Somali current flows from low latitudes to high latitudes in summer.

It has the nature of a cold snap.

2. Causes of warm current in winter.

The northern Indian Ocean sea area has a low latitude and a dry coastal climate with less cloud cover and solar radiation.

strong, the temperature is relatively high all year round, and the solar radiation energy obtained is relatively high - this is the main reason for the high temperature of the seawater; The coast has a mostly dry tropical desert climate.

Without the inflow of large rivers, the seawater is less diluted and therefore has a high salinity; Although the sea area is open to the south, it is located at the equator.

Nearby, coupled with the formation of circulation, the seawater here is less likely to fully communicate with the seawater of the southern ocean, so that the characteristics of high temperature and high salinity of the seawater near the red ant stove can be maintained.

Judgment of warm and cold currents.

To determine whether an ocean current is warm or cold, it can be based on latitude and temperature, and when the judgment results of the two conflict, the temperature will prevail.

1. Latitude. Flowing from low latitudes to high latitudes, that is, from warm sea areas to cold sea areas, is called warm currents; Flowing from high latitudes to low latitudes is a cold snap.

2. Temperature. From high water temperature to low water temperature, Kuanqing or isotherm convex to low water temperature, which is a warm current; A cold snap occurs when the water temperature flows from low to high water temperature, or when the isotherm conves out to high water temperature.

The causes of the Somali warm current and the Somali cold current are as follows:The cause of the warm current is the low latitude of the northern Indian Ocean in winter, the dry coastal climate, less cloud cover, strong solar radiation, and relatively high temperatures throughout the year. The coast is mostly a dry tropical desert climate, with no inflow of major rivers.

As a result, the shore is confined to the shore, and the seawater continues to accumulate, forming a nearshore subsidence, and the surface hot water sinks downwind and southward, forming a warm current.

In summer, the surface waters of the Arabian Sea are blown offshore by the southwest monsoon, while the waters off the nearby East African coast flow to compensate for the loss of seawater, creating an up-compensating current. As a result, the coastal wind is offshore, and the lower cold water is overflowing, and it follows the wind to the north, becoming a cold current flowing from low latitude to high latitude.

Principles of the Ocean Current Mechanism.

Wind is the main driving force of ocean currents, and the deflection force of the earth, the distribution of land and sea, and the undulation of the seabed also have different degrees of influence. For example, geostrophic deflection forces cause ocean currents to shift to the right in the northern hemisphere and to the left in the southern hemisphere. Continental barriers make it impossible for any ocean current to flow around the Earth, and islands or continental protrusions can allow ocean currents to branch.

The Somali warm current and the Somali cold current are caused by the prevailing southwesterly winds in the coastal waters of the Somali Peninsula in summer, which blow the surface sea water near the shore away from the coast, causing the deep sea water to rise due to compensation, forming a strong upwelling and significantly reducing the water temperature, and the ocean current is a cold current.

World currents can be divided into two categories: warm currents and cold currents according to the nature of the seawater. The monsoon currents in the northern Indian Ocean are generally warm currents in both winter and summer, because the sea area is located in the tropical range and the water temperature is high all year round, which is the same reason as the equatorial currents located at low latitudes. However, there are exceptions to the ocean currents off the coast of Somalia.

The formation of the Somali Warm Current

The world ocean currents can be divided into three types according to their causes: wind-sea currents, density currents and compensation currents, and the monsoon currents in the North Indian Ocean belong to wind-sea currents from the perspective of genesis. In the northern part of the Indian Ocean, the tropical monsoon is dominated by seasonal shifts in the position of pressure and wind belts, as well as due to differences in the thermal properties of land and sea, due to the narrowness of the sea area and the lack of northeast trade winds.

From October to March and April of the following year, the Asian continent is enveloped by a strong high pressure (the subtropical high pressure belt moves south), and over the sea surface of the northern Indian Ocean, the northeast monsoon prevails, and the sea water of the Bay of Bengal flows to the southwest, circling the island of Sri Lanka in the south, and together with the water flowing from the Arabian Sea to the southwest, the northeast monsoon current is formed.

Subsequently, it flows south along the coast of the Somali Peninsula to form the Somali Warm Current, and merges with the North Equatorial Warm Current, turns near the equator, and flows eastward along the equator to Sumatra, forming a fairly obvious equatorial countercurrent.

Causes of the Somali cold snap :In summer, the surface waters of the Arabian Sea are blown offshore by the southwest monsoon, and the waters off the nearby East African coast flow to compensate for the loss of seawater, forming an up-compensation current. According to the law of vertical decline in the surface sea temperature of the ocean, the Somali Current, which flows from low latitudes to high latitudes in summer, has the nature of a cold current.

The impact of the Somali current on the summer is a cold current mainly because the coastline of Somalia deviates from the summer monsoon, the coast presents an offshore wind, and the lower cold water floods, which follows the wind to the north, becoming a cold current from low latitude to high latitude, and the impact of the cold current on the coastal climate is cooling and dampness, which aggravates the drought in Somalia in summer.

Causes of the Somali Warm Current:The latitude of the North Indian Ocean is low, the coastal climate is dry, the cloud cover is less, the solar radiation is strong, the temperature is relatively high all year round, and the solar radiation energy obtained is relatively large. This is the main reason for the high temperature of the sea; The coast is mostly a dry tropical desert climate, with no inflow of major rivers, and the sea water is less diluted, so the salinity is high.

Although the sea area is open to the south, because it is located near the equator and the formation of circulation, the seawater here is less likely to fully communicate with the seawater of the southern ocean, so it can maintain the characteristics of high temperature and high salinity of the seawater near the equator.

Classification of ocean currents.

Ocean currents can be divided into warm currents and cold currents according to whether their water temperature is lower or higher than the water temperature of the sea area through which they flow.

1. Warm current. The water temperature is warmer than that of the water flowing through the sea area, which comes from the high water temperature.

2. The temperature of cold water is lower than that of the surrounding water, which comes from a low water temperature. The horizontal velocity of surface currents ranges from a few centimeters per second to 300 centimeters per second, while the horizontal velocity of deep currents is less than 10 centimeters per second. The DC speed is small, from a few centimeters per day to tens of centimeters per hour.

Ocean currents are based on the direction in which they flow, which is the opposite of the definition of wind direction.

The reason for the warm current in Somalia in winter is that the winter wind intersects with the Somali coastline, which makes the shore show an onshore wind, and the seawater continues to accumulate and then sink, forming a nearshore subsidence base uplift, and the surface hot water sinks downwind southward, forming a warm current. The Somali Current is the only current in the world that has a seasonal front, and in winter it is also the only warm current that flows from high latitudes to low latitudes.

Causes of warm currents in winter:

1. The latitude of the North Indian Ocean is low, the coastal climate is dry, the cloud cover is less, the solar radiation is strong, the temperature is relatively high all year round, and the solar radiation energy obtained is relatively large - this is the main reason for the high sea temperature;

2. The coast is mostly dry tropical desert climate, there is no inflow of large rivers, and the sea water is less diluted - so the salinity is high;

3. Although the sea area is open to the south, because it is located near the equator and the formation of circulation, the seawater here is less likely to fully communicate with the seawater of the southern ocean, so it can maintain the characteristics of high temperature and high salinity of the seawater near the equator.