| As two important components of the earth system,the sea and the atmosphere interact with each other on various temporal and spatial scales,regulating the energy balance and water cycle of the entire earth,thereby having a huge impact on climate changes and the natural geographic environment.The atmosphere and oceans have warmed and have posed an important and realistic threat,which is the most important issue that people have to face at present.The South China Sea and the adjacent West Pacific waters are one of the main areas that have a subtle influence on my country's climate change,and temperature is one of the main indicators of the thermal and dynamic conditions of the ocean surface.There is a double-vortex circulation in the South China Sea.In addition,the South China Sea is also affected by the Kuroshio in the East China Sea,which affects the circulation state of the South China Sea through the Bashi Channel and further affects the sea surface temperature of the South China Sea.Only a clear understanding of the marine hydrological structure,temporal and spatial changes and their differences in the sea area can provide a theoretical basis for revealing the impact mechanism of climate change in the study area and predicting future climate and environmental changes.This article uses the sea surface temperature data set from 1871 to 2010 in the SODA?2.2.4 data set.The topographic data used comes from the global seabed topography database released by the American Geophysical Data Center,and the research area is extracted through MATLAB software.Using the traditional empirical orthogonal decomposition method(EOF),moving average method,wavelet analysis,etc.to analyze the surface temperature distribution of the South China Sea and the adjacent West Pacific Ocean from 1871 to 2010,1680 months of surface monthly average temperature data in 140 years Characteristics and their differences,draw the following conclusions:1)The 30-year average maximum surface temperature(29.9?)of the South China Sea and the adjacent Northwest Pacific Ocean appears in the eastern part of the Western Pacific Ocean near the equator;the 30-year average minimum surface temperature(22.5?)appears in the coastal area of South China.The temperature difference in the West Pacific Ocean has the smallest change,and the temperature difference in the South China coast has the largest change.In the northeastern part of the study area,close to the mainland coastline,the temperature rises quickly in spring and summer,and the temperature drops quickly in autumn and winter.This is one of the reasons that this area has become a large change in the sea area of the entire study area.2)Analyzing the spatial distribution of surface sea temperature in the study area,the study sea can be divided into six sea areas: the South China Sea is divided into three areas: from the north to the basic coastal current distribution of the southern China coastal isotherm with 15°N as the boundary,The temperature difference is obvious,divided into S1;the isotherm of the coast of the Indo-China Peninsula south of 15°N is basically parallel to the coastline,almost perpendicular to the latitude,this sea area is divided into S2;the sea area south of 15°N has higher sea temperature,and the temperature difference is larger Small,planned as S3.Due to the influence of the Kuroshio,the temperature of the Bashi Strait sea area is significantly higher than that of the sea area at the same latitude,so a separate area is divided into S4.The West Pacific Ocean is divided into two sea areas: the isotherm to the north is basically distributed along the latitude with the boundary of 12°N,and the temperature difference is obvious.It is divided into P1,and the Sulu Sea and the Sulawesi Sea are affected by the northern equatorial warm current and the equatorial countercurrent.Influence,the year-round high temperature and small temperature difference,are collectively classified as P2.3)In the study area,the 30-year inter-monthly and monthly variation analysis of the selected 22 characteristic points shows that the temperature difference in the study area basically increases from low latitudes to high latitudes,and the higher the latitude,the change in the sea area temperature difference is also The more obvious,the lower the latitude of the sea area,the temperature difference change is the opposite;in addition to the zonal distribution characteristics,the temperature difference also shows the characteristics of increasing from east to west,that is,the temperature difference in the open sea is smaller,and the closer to the inland sea,the greater the change in temperature difference.Great;the sea area near the coast has seen dramatic changes.4)In the South China Sea,affected by topography and ocean currents,the isotherm generally shows a decreasing trend from southeast to northwest,and its direction is basically the same as the direction of the ocean current;in the eastern sea area of the Indo-China Peninsula,the isotherm is approximately parallel to the coast(ie approximately vertical At the line of latitude).In the central part of the Western Pacific Ocean,the distribution of sea surface isotherms is roughly parallel to the latitude.In the Sulawesi Sea,a semi-enclosed water body close to the equator,a lot of solar radiation is obtained,and it is invaded by the North Equatorial Warm Current and blocked by islands so that most of the warm current stays in the Sulawesi Sea.The temperature difference varies throughout the study area.The smallest;but as a relatively closed body of water,the Sulu Sea,blocked by islands,it is difficult for the North Equatorial Warm Current to enter,and its temperature difference is greater than that of the adjacent South China Sea and West Pacific waters at the same latitude.5)Through the analysis of inter-monthly and monthly temperature changes,it can be seen that in the sea area near 18.75°N south of the Tropic of Cancer,the inter-monthly and monthly conversion of its temperature at the multi-year average level shows the characteristics of temperate climate.It shows that the boundary between the tropical and temperate(subtropical)zones of the study area is obviously lower than the latitude of the land.The climatic characteristics of the15.75°N-17.75°N area gradually show a transition from the tropical zone to the temperate zone(subtropical zone),so we can roughly adjust the 16.75°N to the temperate zone(subtropical zone)serves as the climatic boundary between the tropical zone and the temperate zone(subtropical zone)of the sea area.6)In the study area,the surface temperature distribution in 140 years is basically the same as that in 30 years,with little difference: the lowest sea temperature is still on the left side of the coastal continental shelf of Guangdong,China and the island of Taiwan,which is still the shallow surface of the entire study area The area with the greatest temperature variation.The three regions with the highest temperatures are all in the southern seas close to the equator,but the 140-year high-temperature surface area is relatively small.For the 140-year South China Sea,that is,the adjacent West Pacific Ocean,the distribution of the inter-annual amplitude of the surface temperature is basically the same.Only the sea areas close to the coastline have the most significant changes under the new climate base period.7)EOF decomposition of the sea temperature anomaly in the shallow surface layer found that the shallow surface sea temperature in the study area showed positive sea temperature anomalies.The area with the strongest positive anomaly is the waters of the Taiwan Strait of my country,which is the study area.The sea area with the most obvious temperature difference;the area with the weakest positive anomaly is in the central part of the West Pacific Ocean and the sea area near the equator. |
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