The interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) and its relationship with the climate jump in the Northern Hemisphere in the 1960s, are discussed using the data an...The interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) and its relationship with the climate jump in the Northern Hemisphere in the 1960s, are discussed using the data analyses. It is clearly shown that the amplitudes of the NAO and NPO were all increased obviously in the 1960s and the main period of the展开更多
The authors present evidence to suggest that variations in the snow depth over the Tibetan Plateau （TP） are connected with changes of North Atlantic Oscillation （NAO） in winter （JFM）. During the positive phase o...The authors present evidence to suggest that variations in the snow depth over the Tibetan Plateau （TP） are connected with changes of North Atlantic Oscillation （NAO） in winter （JFM）. During the positive phase of NAO, the Asian subtropical westerly jet intensifies and the India-Myanmar trough deepens. Both of these processes enhance ascending motion over the TP. The intensified upward motion, together with strengthened southerlies upstream of the India-Myanmar trough, favors stronger snowfall over the TP, which is associated with East Asian tropospheric cooling in the subsequent late spring （April-May）. Hence, the decadal increase of winter snow depth over the TP after the late 1970s is proposed to be an indicator of the connection between the enhanced winter NAO and late spring tropospheric cooling over East Asia.展开更多
This article discusses the interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO), its relationship with the interdecadal climate variation in China which is associated with ...This article discusses the interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO), its relationship with the interdecadal climate variation in China which is associated with the climate jump in the Northern Hemisphere in the 1960’s, using the data analyses. It is clearly shown that both the amplitudes of the NAO and NPO increase obviously in the 1960’s and the main period of the oscillations changes from 3-4 years before the 1960’s to 8–15 years after the 1960’s. Therefore, interdecadal climate variation in China or the climate jump in the 1960’s is closely related to the anomalies of the NAO and NPO. Key words North Atlantic Oscillation (NAO) - North Pacific Oscillation (NPO) - Climate Jump - Interdecadal climate variation This work was supported by National Key Basic Science Program in China (G1998040903), Chinese Academy of Science and the National Natural Science Fundation of China (Grant No.49823002).The authors are also grateful to Ms. Wang Xuan for typing the manuscript.展开更多
The capabilities of two versions of the Global–Ocean–Atmosphere–Land–System model (i.e. GOALS–2 and GOALS–4) developed at State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), are v...The capabilities of two versions of the Global–Ocean–Atmosphere–Land–System model (i.e. GOALS–2 and GOALS–4) developed at State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), are validated in terms of the simulations of the winter North Atlantic Oscillation (NAO), which is currently the subject of considerable scientific interest. The results show that both GOALS–2 and GOALS–4 exhibit a realistic NAO signal associated with relatively reasonable spatial patterns of sea level pressure, surface air temperature, and precipitation. Generally speaking, the associated patterns of precipitation in GOALSs match better with the observation in comparison with the case of surface temperature. For the imprint of NAO on the ocean, or perhaps a coupling between the two fluids, the associated tripole patterns of the North Atlantic SST anomaly are presented distinctly in GOALS–2, for GOALS-4 however, this is not the case. Spatially, the models’ main deficiencies appear to be that the simulated Icelandic lows shift northward apparently, which in turn result in the blemish of GOALSs in reproducing the accompanied surface wind anomalies. For the interannual and even longer time scale variations of DJF sea level pressure (SLP) over the North Atlantic region, GOALSs reproduce the center with the strongest variability rationally, but the intensities are far weaker than the observation. Key words North Atlantic Oscillation (NAO) - Model evaluation - GOALS model This study was jointly supported by the National key Project (Grant No. 96-908-02-03), the Excel-lent National Key Laboratory Research Project (Grant NO. 49823002), Chinese Academy of Sciences (CAS) under grant “ Bai Ren Ji Hua” for “ Validation of Coupled Climate Models”, and IAP innova-tion fund (No.8-1204).The authors gratefully acknowledge Dv. Jin Xuingze, Mr. Liu Xiying in IAP /LASG, and Dr. Gong Daoyi in Geophysical Department of Peking University for providing ardent help.展开更多
Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase...Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase, Icelandic Low is obviously deepened and shifts northwards (southwards). Simultaneously, the Subtropical High over the North Atlantic is also intensified, and moves northwards (southwards). Those anomalies strengthen (weaken) westerly between Icelandic Low and the Subtropical High, and further result in positive (negative) sea surface temperature (SST) anomalies in the mid-latitude of the North Atlantic, and increase (decrease) the warm water transportation from the mid-latitude to the Barents Sea, which causes positive (negative) mixed-layer water temperature anomalies in the south part of the Barents Sea. Moreover, the distribution of anomaly air temperature clearly demonstrates warming (cooling) in northern Europe and the subarctic regions (including the Barents Sea) and cooling展开更多
Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtrac...Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic os- cillations have been found in the global mean Earth temperature anomaly （HadCRUT4） and global mean sea level （GMSL）. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth＇s rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth＇s rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.展开更多
Based on the viewpoint that the North Atlantic Oscillation(NAO)has an intrinsic timescale of approximate two weeks and can be treated as an initial value problem,targeted observations for improving the prediction of t...Based on the viewpoint that the North Atlantic Oscillation(NAO)has an intrinsic timescale of approximate two weeks and can be treated as an initial value problem,targeted observations for improving the prediction of the onset of NAO events are investigated by using the conditional nonlinear optimal perturbation(CNOP)method with a quasigeostrophic model.The results show that flow-dependent sensitive areas for the prediction of NAO onset are mainly located over North Atlantic and its upstream regions.Targeted observations over the main sensitive areas could improve NAO onset prediction in most cases(approximately 75%)due to reduced errors in anomalous eddy vorticity forcing(EVF)projection in the typical NAO mode.Moreover,a flow-independent sensitive area is determined based on the winter climatological flow,which is located over North America and its adjacent ocean.The NAO onset prediction can also be improved by targeted observations over the flow-independent sensitive area,but the skill improvement is somewhat lower than that derived from observations over the flow-dependent sensitive area.The above results indicate that targeted observations over sensitive areas identified by the CNOP method can help to improve the onset prediction of NAO events.展开更多
文摘The interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO) and its relationship with the climate jump in the Northern Hemisphere in the 1960s, are discussed using the data analyses. It is clearly shown that the amplitudes of the NAO and NPO were all increased obviously in the 1960s and the main period of the
基金supported by the R&D Special Fund for Public Welfare Industry (meteorology) under Grant Nos. GYHY200706010 and GYHY200806020 the National Science Foundation of China under Grant Nos. 40625014 and 40821092 National Key Project of Scientific and Technical Supporting Programs under Grant Nos. 2007BAC03A01 and 2007BAC29B03
文摘The authors present evidence to suggest that variations in the snow depth over the Tibetan Plateau （TP） are connected with changes of North Atlantic Oscillation （NAO） in winter （JFM）. During the positive phase of NAO, the Asian subtropical westerly jet intensifies and the India-Myanmar trough deepens. Both of these processes enhance ascending motion over the TP. The intensified upward motion, together with strengthened southerlies upstream of the India-Myanmar trough, favors stronger snowfall over the TP, which is associated with East Asian tropospheric cooling in the subsequent late spring （April-May）. Hence, the decadal increase of winter snow depth over the TP after the late 1970s is proposed to be an indicator of the connection between the enhanced winter NAO and late spring tropospheric cooling over East Asia.
基金This work was supported by National Key Basic Science Program in China !(G 1998040903)Chinese Academy of Science and the Nat
文摘This article discusses the interannual variation of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO), its relationship with the interdecadal climate variation in China which is associated with the climate jump in the Northern Hemisphere in the 1960’s, using the data analyses. It is clearly shown that both the amplitudes of the NAO and NPO increase obviously in the 1960’s and the main period of the oscillations changes from 3-4 years before the 1960’s to 8–15 years after the 1960’s. Therefore, interdecadal climate variation in China or the climate jump in the 1960’s is closely related to the anomalies of the NAO and NPO. Key words North Atlantic Oscillation (NAO) - North Pacific Oscillation (NPO) - Climate Jump - Interdecadal climate variation This work was supported by National Key Basic Science Program in China (G1998040903), Chinese Academy of Science and the National Natural Science Fundation of China (Grant No.49823002).The authors are also grateful to Ms. Wang Xuan for typing the manuscript.
基金This study was jointly supported by the National key Project !(Grant No. 96-908-02-03) the Excellent National Key Laboratory
文摘The capabilities of two versions of the Global–Ocean–Atmosphere–Land–System model (i.e. GOALS–2 and GOALS–4) developed at State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), are validated in terms of the simulations of the winter North Atlantic Oscillation (NAO), which is currently the subject of considerable scientific interest. The results show that both GOALS–2 and GOALS–4 exhibit a realistic NAO signal associated with relatively reasonable spatial patterns of sea level pressure, surface air temperature, and precipitation. Generally speaking, the associated patterns of precipitation in GOALSs match better with the observation in comparison with the case of surface temperature. For the imprint of NAO on the ocean, or perhaps a coupling between the two fluids, the associated tripole patterns of the North Atlantic SST anomaly are presented distinctly in GOALS–2, for GOALS-4 however, this is not the case. Spatially, the models’ main deficiencies appear to be that the simulated Icelandic lows shift northward apparently, which in turn result in the blemish of GOALSs in reproducing the accompanied surface wind anomalies. For the interannual and even longer time scale variations of DJF sea level pressure (SLP) over the North Atlantic region, GOALSs reproduce the center with the strongest variability rationally, but the intensities are far weaker than the observation. Key words North Atlantic Oscillation (NAO) - Model evaluation - GOALS model This study was jointly supported by the National key Project (Grant No. 96-908-02-03), the Excel-lent National Key Laboratory Research Project (Grant NO. 49823002), Chinese Academy of Sciences (CAS) under grant “ Bai Ren Ji Hua” for “ Validation of Coupled Climate Models”, and IAP innova-tion fund (No.8-1204).The authors gratefully acknowledge Dv. Jin Xuingze, Mr. Liu Xiying in IAP /LASG, and Dr. Gong Daoyi in Geophysical Department of Peking University for providing ardent help.
基金the National Natural Science Foundation of China (Grant No. 49905003).
文摘Variations of winter Arctic sea ice bordering on the North Atlantic are closely related to climate variations in the same region. When winter North Atlantic Oscillation (NAO) index is positive (negative) anomaly phase, Icelandic Low is obviously deepened and shifts northwards (southwards). Simultaneously, the Subtropical High over the North Atlantic is also intensified, and moves northwards (southwards). Those anomalies strengthen (weaken) westerly between Icelandic Low and the Subtropical High, and further result in positive (negative) sea surface temperature (SST) anomalies in the mid-latitude of the North Atlantic, and increase (decrease) the warm water transportation from the mid-latitude to the Barents Sea, which causes positive (negative) mixed-layer water temperature anomalies in the south part of the Barents Sea. Moreover, the distribution of anomaly air temperature clearly demonstrates warming (cooling) in northern Europe and the subarctic regions (including the Barents Sea) and cooling
基金supported by Russian Foundation for Basic Research (16-05-00753)partially supported by NSF/IGFA (ICER-1342644)
文摘Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic os- cillations have been found in the global mean Earth temperature anomaly （HadCRUT4） and global mean sea level （GMSL）. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth＇s rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth＇s rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.
基金Supported by the National Natural Science Foundation of China(41775001)Technology Development Foundation of Chinese Academy of Meteorological Sciences(2018KJ036).
文摘Based on the viewpoint that the North Atlantic Oscillation(NAO)has an intrinsic timescale of approximate two weeks and can be treated as an initial value problem,targeted observations for improving the prediction of the onset of NAO events are investigated by using the conditional nonlinear optimal perturbation(CNOP)method with a quasigeostrophic model.The results show that flow-dependent sensitive areas for the prediction of NAO onset are mainly located over North Atlantic and its upstream regions.Targeted observations over the main sensitive areas could improve NAO onset prediction in most cases(approximately 75%)due to reduced errors in anomalous eddy vorticity forcing(EVF)projection in the typical NAO mode.Moreover,a flow-independent sensitive area is determined based on the winter climatological flow,which is located over North America and its adjacent ocean.The NAO onset prediction can also be improved by targeted observations over the flow-independent sensitive area,but the skill improvement is somewhat lower than that derived from observations over the flow-dependent sensitive area.The above results indicate that targeted observations over sensitive areas identified by the CNOP method can help to improve the onset prediction of NAO events.
