Geophysical signals N of interest are often contained in a parent signal G that also contains a seasonal signal X at a known frequency fX. The general issues associated with identifying N and X and their separation fr...Geophysical signals N of interest are often contained in a parent signal G that also contains a seasonal signal X at a known frequency fX. The general issues associated with identifying N and X and their separation from G are considered for the case where G is the Pacific sea surface temperature monthly data, SST3.4;N is the El Ni?o/La Ni?a phenomenon and the seasonal signal X is at a frequency of 1/(12 months). It is shown that the commonly used climatology method of subtracting the average seasonal values of SST3.4 to produce the widely used anomaly index Nino3.4 is shown not to remove the seasonal signal. Furthermore, it is shown that the climatology method will always fail. An alternative method is presented in which a 1/fX (= 12 months) moving average filter F is applied to SST3.4 to generate an El Ni?o/La Ni?a index NL that does not contain a seasonal signal. Comparison of NL and Nino3.4 shows, among other things, that estimates of the relative magnitudes of El Ni?os from index NL agree with observations but estimates from index Nino3.4 do not. These results are applicable to other geophysical measurements.展开更多
通过对近百年 El Nino/ L a Nina事件与北京气候相关性研究发现 ,El Nino/ L aNina事件与北京夏季 ( 6～ 8月 )降水、平均最高气温 ( 7月 )和冬季 ( 1月 )平均最低气温之间相互关系显著。 El Nino事件与夏季降水、冬季平均最低气温呈负...通过对近百年 El Nino/ L a Nina事件与北京气候相关性研究发现 ,El Nino/ L aNina事件与北京夏季 ( 6～ 8月 )降水、平均最高气温 ( 7月 )和冬季 ( 1月 )平均最低气温之间相互关系显著。 El Nino事件与夏季降水、冬季平均最低气温呈负相关 ,与夏季平均最高气温呈正相关 ,造成降水减少 ,气温年较差增大 ,大陆性增强的气候特点。L a Nina事件与夏季降水、冬季平均最低气温呈正相关 ,与夏季平均最高气温呈负相关 ,使降水增加 ,气温年较差减小 。展开更多
Statistic and typical-year composition methods are used to study the northwest Pacific typhoonactivities in relation with the El Nino and La Nina events. The result indicates that the typhoon tends to be inactive in t...Statistic and typical-year composition methods are used to study the northwest Pacific typhoonactivities in relation with the El Nino and La Nina events. The result indicates that the typhoon tends to be inactive in the El Nino years and active in the La Nina years and it is also dependent on the onset and ending time andintensity of the events and areas of genesis of typhoons. With statistic features of the frequency of typhoon activity in the EI Nino and La Nina years and the time-lag correlation between the frequency and sea surface temperature (SST), useful information is provided for the prediction of typhoon occurrence. In addition, the singularvalues disassemble (SVD) method is applied to study the correlation between the geopotential field and SST fief(l.The result shows that the air-sea coupling in the EI Nino years is unfavorable for the typhoon to develop. whichtake place with a smaller number. Opposite situations are found with the La Nina years.展开更多
伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的...伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的关联。结果显示，El Nino 当年冬季和次年春夏季我国东部大部分地区以多雨为主，La Nina 年则相反；长江中下游地区降水显著异常偏多发生在 El Nino 次年春季，且此时长江流域以及河套地区降水量均显著增加，但 La Nina 次年春季该地区雨量无明显变化；El Nino 次年春季和 La Nina 次年夏季西南地区易发生干旱。结果表明 El Nino 和 La Nina 对中国东部季节降水的影响存在非对称性，对于部分地区具有一定的预测意义。展开更多
A class of coupled system of the E1 Nino/La Nina-Southern Oscillation （ENSO） mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic...A class of coupled system of the E1 Nino/La Nina-Southern Oscillation （ENSO） mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic behavior of solution for corresponding problem is considered.展开更多
The analyses on the responses of partial pressure difference between sea and air (PCO2), and total dissolved CO2 concentration (TCO2), to abnormal air-sea event in different seasons, were based on observational data m...The analyses on the responses of partial pressure difference between sea and air (PCO2), and total dissolved CO2 concentration (TCO2), to abnormal air-sea event in different seasons, were based on observational data measured during cruises from Nov. 1986 to Dec 1997 in area of 22°N - 18°N, 114°E-130°E. The results indicated that in every season, TCO2 was high and PCO2 was positive during onset and mature period of El Nino, but they were low and negative respectively during La Nina. Before and after El Nino, partial pressure of CO2 in the sea and air were in the state of equilibrium. Both PCO2 (air) and PCO2 (air) had same responses to E1 Nino in each season. PCO2 (air) and PCO2 (sw) were high during mature period of El Nino were low before and in onset period of El Nino PCO2 and PCO2 (sw) reached peak value during E1 Nino and variation of PCO2 and PCO2 (sw) were same The mean exchange of CO2 from sea to air (flux) reached peak value during El Nino in autumn, and decreased during La Nina. Before and after El Nino the flux is weak, but in opposite direction from air to sea. According to the 1986-1993 average the characteristics of response of TCO2 anomaly to El Nino and La Nina and the range of outstanding variation in different season were discussed. From above it can be deduced some signals showing ENSO event as follows: in Oct.1995, El Nino of 91/95 was over: In May 1995 it is before a new El Nino: In July 1997 it is in onset of new El Nino; In Dec.1997 it is in the mature stage of E1 Nino event.展开更多
-By using the sea surface temperature (SST) index of the Equatorial Pacific Ocean provided by Climate Analysis Center of U. S. A. , the numerical criteria of El Nino and La Nina events and their quantitative character...-By using the sea surface temperature (SST) index of the Equatorial Pacific Ocean provided by Climate Analysis Center of U. S. A. , the numerical criteria of El Nino and La Nina events and their quantitative characteristics were calculated. Results show that the El Nino event was characterized with strong intensity, shorter life cycle and significant mature phase; however, the La Nina event has longer live cycle, weak intensity, insignificant mature phase. Through teleconnection analysis, it is found that the intensity index of SST over the Equatorial Pacific Ocean leads the intensity index of subtropical high by six months or so. During the El Nino years, the tropical cyclone over the northwestern Pacific is fewer than normal but stronger, and its genesis area shifts southeastward apparently; while in the La Nina years the number of tropical cyclones are larger.展开更多
The El Nino Index, defined as 4 intensities (very strong, strong, moderate, weak) in Oceanic Niño Index (ONI), was positively correlated with the average sunspot number at each intensity. The La Niña...The El Nino Index, defined as 4 intensities (very strong, strong, moderate, weak) in Oceanic Niño Index (ONI), was positively correlated with the average sunspot number at each intensity. The La Niña Index, defined as 3 intensities (strong, moderate, weak) in ONI, was negatively correlated with the average sunspot number from 1954 to 2017. It appears that very strong El Niño events occur frequently during the maximal sunspot number while strong La Niña events more often occur during the minimal sunspot number. Since greenhouse-gas is continuously increased, it is therefore proposed that the maximal sunspot number is a major parameter for prediction of El Niño while the minimal sunspot number applies in the same way for La Niña. El Nino/La Nina events can be classified as four typical cases depending upon the submarine volcanic activities at seamounts in Antarctica and South America. The Sea Surface Temperature (SST) of the South and Central Americas are warmer than SST of East Australian Current (EAC), due to the strong volcanic eruptions in the Seamounts and the Ridges in South and Central Americas. This results in the Central Pacific Current (CPC) flowing from east to west due to the second law of thermodynamics for thermal flow from hot source to cold sink. In contrast the opposite direction is made if SST in EAC is warmer than SST in the Central/South American Seamounts and Ridges, due to the strong volcanic eruptions in the Antarctic Seamounts and Ridges. Chicago was selected as a case study for the relationship between extreme cold weather conditions and minimal sunspot number. Previous attempts at predicting weather patterns in Chicago have largely failed. The years of the record low temperatures in Chicago were significantly correlated with the years of the minimal sunspot number from 1873 to 2019. It is forecast that there may occur a weak La Niña in 2019 and another record low temperature in Chicago in January of 2020 due to the phase of the minimal sunspot number in 2019. It may be possible to predict very strong El Nino events with the year of maximal sunspot number as El Niño Index (R2 = 0.7363) and the years of strong volcanic eruption in the Galapagos Hot Spot (GHS) (R2 = 0.9939), respectively. An El Niño event is thus expected during the year of strong volcanic eruption in the GHS. Strong La Niña events can be expected during the year of minimal sunspot number with La Niña Index (R2 = 0.9922). Record low temperatures in Chicago can be also predicted (R2 = 0.9995) during the year of the minimal sunspot number, as was recently the case in January, 2019.展开更多
The curved surface of the maximum sea temperature anomaly (MSTA) was created from the JEDAC subsurface sea temperature anomaly data at the tropical Pacific between 1955 and 2000. It is quite similar to the depth distr...The curved surface of the maximum sea temperature anomaly (MSTA) was created from the JEDAC subsurface sea temperature anomaly data at the tropical Pacific between 1955 and 2000. It is quite similar to the depth distribution of the 20℃ isotherm, which is usually the replacement of thermocline. From the distribution and moving trajectory of positive or negative sea temperature anomalies (STA) on the curved surface we analyzed all the El Nino and La Nina events since the later 1960s. Based on the analyses we found that, using the subsurface warm pool as the beginning point, the warm or cold signal propagates initially eastward and upward along the equatorial curved surface of MSTA to the eastern Pacific and stays there several months and then to (urn north, usually moving westward near 10°N to western Pacific and finally propagates southward to return to warm pool to form an off-equator closed circuit. It takes about 2 to 4 years for the temperature anomaly to move around the cycle. If the STA of warm (cold) water is strong enough, there will be two successive El Nino (La Nina) events during the period of 2 to 4 years. Sometime, it becomes weak in motion due to the unsuitable oceanic or atmospheric condition. This kind process may not be considered as an El Nino ( La Nina) event, but the moving trajectory of warm (cold) water can still be recognized. Because of the alternate between warm and cold water around the circuits, the positive (negative) anomaly signal in equatorial western Pacific coexists with negative (positive) anomaly signal near 10°N in eastern Pacific before the outbreak of El Nino (La Nina) event. The signals move in the opposite directions. So it appears as El Nino (La Nina) in equator at 2-4 years intervals. The paper also analyzed several exceptional cases and discussed the effect and importance of oceanic circulation in the evolution of El Nino/ La Nina event.展开更多
The Banda Sea is one of the routes of global ocean currents that move from the Pacific Ocean to the Indian Ocean.This flow is known as Indonesian Through Flow(ITF).The Banda Sea is an area where warm and cold water ma...The Banda Sea is one of the routes of global ocean currents that move from the Pacific Ocean to the Indian Ocean.This flow is known as Indonesian Through Flow(ITF).The Banda Sea is an area where warm and cold water masses meet,so it has the potential for a thermal front.This study aims to understand the variability of thermal front in the Banda Sea during the El Nino Southern Oscillation period.Southern Oscillation Index(SOI)and sea surface temperature(SST)data in 2010,2012 and 2015 were used in this study.SOI data was obtained from http://www.bom.gov.au and SST data were obtained from http://oceancolor.gsfc.nasa.gov.The data were processed using ArcGIS 10.4 software and Ms.Office 2013.The results showed the La Nina period occurs in July-December 2010,the Normal period occurs in July-December 2012,and the El Nino period occurs in May-October 2015.In general,during La Nina,the mean SST has higher values than the other periods.On the other hand,the highest thermal front occurs during the El Niño period(10584),followed by the Normal period(7544)and the lowest during the La Niña period(5961),respectively.展开更多
文摘Geophysical signals N of interest are often contained in a parent signal G that also contains a seasonal signal X at a known frequency fX. The general issues associated with identifying N and X and their separation from G are considered for the case where G is the Pacific sea surface temperature monthly data, SST3.4;N is the El Ni?o/La Ni?a phenomenon and the seasonal signal X is at a frequency of 1/(12 months). It is shown that the commonly used climatology method of subtracting the average seasonal values of SST3.4 to produce the widely used anomaly index Nino3.4 is shown not to remove the seasonal signal. Furthermore, it is shown that the climatology method will always fail. An alternative method is presented in which a 1/fX (= 12 months) moving average filter F is applied to SST3.4 to generate an El Ni?o/La Ni?a index NL that does not contain a seasonal signal. Comparison of NL and Nino3.4 shows, among other things, that estimates of the relative magnitudes of El Ni?os from index NL agree with observations but estimates from index Nino3.4 do not. These results are applicable to other geophysical measurements.
文摘Statistic and typical-year composition methods are used to study the northwest Pacific typhoonactivities in relation with the El Nino and La Nina events. The result indicates that the typhoon tends to be inactive in the El Nino years and active in the La Nina years and it is also dependent on the onset and ending time andintensity of the events and areas of genesis of typhoons. With statistic features of the frequency of typhoon activity in the EI Nino and La Nina years and the time-lag correlation between the frequency and sea surface temperature (SST), useful information is provided for the prediction of typhoon occurrence. In addition, the singularvalues disassemble (SVD) method is applied to study the correlation between the geopotential field and SST fief(l.The result shows that the air-sea coupling in the EI Nino years is unfavorable for the typhoon to develop. whichtake place with a smaller number. Opposite situations are found with the La Nina years.
文摘伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的关联。结果显示，El Nino 当年冬季和次年春夏季我国东部大部分地区以多雨为主，La Nina 年则相反；长江中下游地区降水显著异常偏多发生在 El Nino 次年春季，且此时长江流域以及河套地区降水量均显著增加，但 La Nina 次年春季该地区雨量无明显变化；El Nino 次年春季和 La Nina 次年夏季西南地区易发生干旱。结果表明 El Nino 和 La Nina 对中国东部季节降水的影响存在非对称性，对于部分地区具有一定的预测意义。
基金The National Natural Science Foundation of China under contract Nos 90111011 and 10471039the National Key Project for Basics Research of China under contract Nos 2003CB415101-03 and 2004CB418304+1 种基金the Knowledge Innovation Project of the Chinese Academy of Sciences under contract NO.KZCXZ-YW-Q03-08LASG State Key Laboratory Special Fund and the E-Insitutes of Shanghai Municipal Education Commission under contract NO.N.E03004
文摘A class of coupled system of the E1 Nino/La Nina-Southern Oscillation （ENSO） mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic behavior of solution for corresponding problem is considered.
文摘The analyses on the responses of partial pressure difference between sea and air (PCO2), and total dissolved CO2 concentration (TCO2), to abnormal air-sea event in different seasons, were based on observational data measured during cruises from Nov. 1986 to Dec 1997 in area of 22°N - 18°N, 114°E-130°E. The results indicated that in every season, TCO2 was high and PCO2 was positive during onset and mature period of El Nino, but they were low and negative respectively during La Nina. Before and after El Nino, partial pressure of CO2 in the sea and air were in the state of equilibrium. Both PCO2 (air) and PCO2 (air) had same responses to E1 Nino in each season. PCO2 (air) and PCO2 (sw) were high during mature period of El Nino were low before and in onset period of El Nino PCO2 and PCO2 (sw) reached peak value during E1 Nino and variation of PCO2 and PCO2 (sw) were same The mean exchange of CO2 from sea to air (flux) reached peak value during El Nino in autumn, and decreased during La Nina. Before and after El Nino the flux is weak, but in opposite direction from air to sea. According to the 1986-1993 average the characteristics of response of TCO2 anomaly to El Nino and La Nina and the range of outstanding variation in different season were discussed. From above it can be deduced some signals showing ENSO event as follows: in Oct.1995, El Nino of 91/95 was over: In May 1995 it is before a new El Nino: In July 1997 it is in onset of new El Nino; In Dec.1997 it is in the mature stage of E1 Nino event.
文摘-By using the sea surface temperature (SST) index of the Equatorial Pacific Ocean provided by Climate Analysis Center of U. S. A. , the numerical criteria of El Nino and La Nina events and their quantitative characteristics were calculated. Results show that the El Nino event was characterized with strong intensity, shorter life cycle and significant mature phase; however, the La Nina event has longer live cycle, weak intensity, insignificant mature phase. Through teleconnection analysis, it is found that the intensity index of SST over the Equatorial Pacific Ocean leads the intensity index of subtropical high by six months or so. During the El Nino years, the tropical cyclone over the northwestern Pacific is fewer than normal but stronger, and its genesis area shifts southeastward apparently; while in the La Nina years the number of tropical cyclones are larger.
基金the University of Suwon and G-Land of South Korea for their financial supports.
文摘The El Nino Index, defined as 4 intensities (very strong, strong, moderate, weak) in Oceanic Niño Index (ONI), was positively correlated with the average sunspot number at each intensity. The La Niña Index, defined as 3 intensities (strong, moderate, weak) in ONI, was negatively correlated with the average sunspot number from 1954 to 2017. It appears that very strong El Niño events occur frequently during the maximal sunspot number while strong La Niña events more often occur during the minimal sunspot number. Since greenhouse-gas is continuously increased, it is therefore proposed that the maximal sunspot number is a major parameter for prediction of El Niño while the minimal sunspot number applies in the same way for La Niña. El Nino/La Nina events can be classified as four typical cases depending upon the submarine volcanic activities at seamounts in Antarctica and South America. The Sea Surface Temperature (SST) of the South and Central Americas are warmer than SST of East Australian Current (EAC), due to the strong volcanic eruptions in the Seamounts and the Ridges in South and Central Americas. This results in the Central Pacific Current (CPC) flowing from east to west due to the second law of thermodynamics for thermal flow from hot source to cold sink. In contrast the opposite direction is made if SST in EAC is warmer than SST in the Central/South American Seamounts and Ridges, due to the strong volcanic eruptions in the Antarctic Seamounts and Ridges. Chicago was selected as a case study for the relationship between extreme cold weather conditions and minimal sunspot number. Previous attempts at predicting weather patterns in Chicago have largely failed. The years of the record low temperatures in Chicago were significantly correlated with the years of the minimal sunspot number from 1873 to 2019. It is forecast that there may occur a weak La Niña in 2019 and another record low temperature in Chicago in January of 2020 due to the phase of the minimal sunspot number in 2019. It may be possible to predict very strong El Nino events with the year of maximal sunspot number as El Niño Index (R2 = 0.7363) and the years of strong volcanic eruption in the Galapagos Hot Spot (GHS) (R2 = 0.9939), respectively. An El Niño event is thus expected during the year of strong volcanic eruption in the GHS. Strong La Niña events can be expected during the year of minimal sunspot number with La Niña Index (R2 = 0.9922). Record low temperatures in Chicago can be also predicted (R2 = 0.9995) during the year of the minimal sunspot number, as was recently the case in January, 2019.
基金This work was supported by the National Natural Science Foundation of China under Grant No.40126002.
文摘The curved surface of the maximum sea temperature anomaly (MSTA) was created from the JEDAC subsurface sea temperature anomaly data at the tropical Pacific between 1955 and 2000. It is quite similar to the depth distribution of the 20℃ isotherm, which is usually the replacement of thermocline. From the distribution and moving trajectory of positive or negative sea temperature anomalies (STA) on the curved surface we analyzed all the El Nino and La Nina events since the later 1960s. Based on the analyses we found that, using the subsurface warm pool as the beginning point, the warm or cold signal propagates initially eastward and upward along the equatorial curved surface of MSTA to the eastern Pacific and stays there several months and then to (urn north, usually moving westward near 10°N to western Pacific and finally propagates southward to return to warm pool to form an off-equator closed circuit. It takes about 2 to 4 years for the temperature anomaly to move around the cycle. If the STA of warm (cold) water is strong enough, there will be two successive El Nino (La Nina) events during the period of 2 to 4 years. Sometime, it becomes weak in motion due to the unsuitable oceanic or atmospheric condition. This kind process may not be considered as an El Nino ( La Nina) event, but the moving trajectory of warm (cold) water can still be recognized. Because of the alternate between warm and cold water around the circuits, the positive (negative) anomaly signal in equatorial western Pacific coexists with negative (positive) anomaly signal near 10°N in eastern Pacific before the outbreak of El Nino (La Nina) event. The signals move in the opposite directions. So it appears as El Nino (La Nina) in equator at 2-4 years intervals. The paper also analyzed several exceptional cases and discussed the effect and importance of oceanic circulation in the evolution of El Nino/ La Nina event.
文摘The Banda Sea is one of the routes of global ocean currents that move from the Pacific Ocean to the Indian Ocean.This flow is known as Indonesian Through Flow(ITF).The Banda Sea is an area where warm and cold water masses meet,so it has the potential for a thermal front.This study aims to understand the variability of thermal front in the Banda Sea during the El Nino Southern Oscillation period.Southern Oscillation Index(SOI)and sea surface temperature(SST)data in 2010,2012 and 2015 were used in this study.SOI data was obtained from http://www.bom.gov.au and SST data were obtained from http://oceancolor.gsfc.nasa.gov.The data were processed using ArcGIS 10.4 software and Ms.Office 2013.The results showed the La Nina period occurs in July-December 2010,the Normal period occurs in July-December 2012,and the El Nino period occurs in May-October 2015.In general,during La Nina,the mean SST has higher values than the other periods.On the other hand,the highest thermal front occurs during the El Niño period(10584),followed by the Normal period(7544)and the lowest during the La Niña period(5961),respectively.
