Climate Change Around Bohai Region During1956to2011and Its Relationship With ENSO

Continuity and space according to the China National Meteorological Center BohaiRim better distribution of45sites monthly and yearly average temperature and precipitationdata and Characterization of ENSO SST data (sea surface temperature and the SouthernOscillation Index SOI),the use of various statistical methods to analyze the Bohai Rimvariation of temperature,precipitation, and analyzed from the point of view of time BohaiRim interannual temperature and precipitation trends and the changing seasons;temperatureand precipitation mutation analysis;from space angle on the analysis of the temperature, thespatial distribution of annual and seasonal precipitation changes;temperature,precipitationcyclical changes.Two aspects of change from the time and space to analyze the trend ofclimate change around Bohai region for nearly56years.And further analysis of aroundBohai region temperature and precipitation and ENSO investigate the relationship betweentemperature and precipitation mechanism of the Bohai Sea region.The followingconclusions:(1)1956-2011Bohai Rim climate change tend to warm and dry,the annual averagetemperature rise of0.188°C/10a average annual precipitation reduce-16.415mm/10a.aroundBohai region in the past56years throughout the year, the four seasons and each month theaverage temperature experienced an increasing trend of rising temperatures in the winter andspring of magnitude greater than in summer and autumn,winter temperatures rise sharply inFebruary,and spring temperatures significantly The increase is driven by rising temperaturesin March and April.The past56years,the precipitation decreasing trend In addition to the thespring precipitation increasing trend,the other three quarters of precipitation showed adecreasing trend in summer rainfall reduction blessing greatly reduced annual precipitationin autumn and winter,the main summer rainfall seasons precipitation most seasons.Decreasing precipitation in July and August led decrease in summer rainfall. Theyear-on-year increase of precipitation in February and March is the reason for the increase ofspring precipitation.Overall,the summer rainfall divide is greater than the other three quarters.Generally speaking,the Bohai Rim climate change is consistent with the trend of globalwarming. (2)1956-2011,around Bohai region, annual and seasonal temperature have differentlevels of mutation,a generally upward trend is consistent with the trend of global warming.The mutation occurred after70years of the19th century, temperatures rise more evidentafter this period, the warming trend has intensified around Bohai region.Annual and seasonalprecipitation in the past56years have different levels of mutations in a generally downwardtrend, in addition to the spring outside.Mutations occur more precipitation decreasing trend.(3)1956-2011years the Bohai Rim spatial distribution of annual and seasonaltemperature are very different.In general,there are two temperature variation from north tosouth, from east to west,the temperature gradually increased.The same time period, northernHebei, Liaoning,eastern and Taishan average temperature is low,most of Shandong andHebei southern high temperatures;temperature is the temperature difference of the Bohai Searegion throughout the year and around the Four Seasons, where the winter temperature is thetemperature difference followed the fall of the temperature difference in the14℃to15℃,around Bohai region in the past56years the spatial distribution of annual and seasonalprecipitation are very different.General,there are two from north to south,graduallydecreasing from southeast to northwest precipitation precipitation variation.The same timeperiod,the less precipitation in northern Hebei,Liaoning southeast of Shandong in easternand southern more precipitation;the Bohai Sea seasonal precipitation obvious differencesshow uneven temporal distribution of precipitation by the Bohai Rim,where summer rainfallThe other three quarters of precipitation are less;around the precipitation difference betweenthe summer rainfall up to480mm, winter precipitation smallest difference is40mm.(4) The annual average temperature round Bohai region has a first main period of of21a and second main cycle of13-14a in1956-2011.In the spring, summer and winter, thetemperature has an obvious cycle, respectively11a,28-19a,21a, and the autumn airtemperature has more than one cycle.In the past56years round Bohai region, there is first acycle of about17a years precipitation.The summer precipitation cycle is consistent with theannual precipitation cycle,which is also17a. And spring, autumn and winter precipitationshows multiple cycles.(5) EL Nino event,the average annual temperature began to rise,the first two yearsincreased significantly;LA Nina event,the temperature slightly lower.EL Nino eventoccurs,and began to reduce annual precipitation,the second annual precipitation increased or maximized;just a year of EL Nino events occurred less precipitation,the EL Nino occurs twoconsecutive years,the first two annual precipitation increased significantly.In LA Ninaevent,down slightly less precipitation.Lag period from six computational analysis can beseen,SSTAwith temperature,precipitation in the EL Nino event occurs negatively correlated,LANina event were positively correlated.In lag1-4months,ENSO on the impact of the BohaiSea region to achieve a relatively large temperature;2-4months in the lag time,ENSO eventsimpact on precipitation reaches relatively large.In LA Nina event occurred during the sameperiod,SSTAon different parts of the Bohai Sea temperature hysteresis is remarkable.The study further shows that precipitation and temperature changes might be influenced bysea surface temperature by using wavelet analysis. The impacts of ENSO on temperature aremore significant than the precipitation.