Atmospheric moisture transport plays an important role in latent heat release and hydrologic interactions in the Arctic.In recent years,with the rapid decline in sea ice,this transport has changed.Here,we calculated t...Atmospheric moisture transport plays an important role in latent heat release and hydrologic interactions in the Arctic.In recent years,with the rapid decline in sea ice,this transport has changed.Here,we calculated the vertically integrated atmospheric moisture meridional transport(AMTv)from two global reanalysis datasets,from1979–2015,and found moisture pathways into the central Arctic.Four stable pathways showed an occurrence frequency greater than 70%,and these pathways exhibited a perennial seasonal pattern in the atmosphere above the Laptev Sea Pathway(LSP),Canadian Arctic Archipelago Pathway(CAAP),both sides of the Greenland plateau.Another seasonal pathway appeared above the east of the Chukchi Sea(CSP)during the melting/freezing months(March to September).Through these pathways,AMTv contributed a total moisture exchange of60%–80%—averaged over a 75°N circle—and focused on the low troposphere.Transports across the LSP,CSP and CAAP pathways likely create an enclosed moisture route.Meridional moisture fluxes are intensified in the Pacific sector of Arctic(PSA),especially during melting/freezing months.AMTv interannual variabilities are illustrated mainly in the Laptev Sea and the east Greenland pathway.Results indicate that accompanying a tendency for a stronger Beaufort Sea High in this sea level pressure field,AMTv through PSA pathways,switched from output to input,and approximately 960 km^3 of equivalent liquid water was transferred into the central Arctic during each decade.The detrended AMTv increment is highly correlated with the rapid decline of old ice areas(correlation coefficient is–0.78)for their synchronous fluctuations in the 1980 s and the last decade.展开更多
With the objective of providing a relatively accurate and complete diagram,the global scale interbasin transport of atmospheric moisture on the basis of the NCEP/NCAR reanalysis data for the period 1980 to 1994 is eva...With the objective of providing a relatively accurate and complete diagram,the global scale interbasin transport of atmospheric moisture on the basis of the NCEP/NCAR reanalysis data for the period 1980 to 1994 is evaluated.The results show that the net zonal vapor flux for the Pacific,the Atlantic and the Indian Oceans is 0.25 Sv,—0.68 Sv and —0.29 Sv respectively.The marking differences in the zonal moisture budget among individual basins are speculated as the reason that dominates the differences in the salinity between the Pacific and the Atlantic Oceans.Though current evaluation on the net zonal moisture flux for the Atlantic basin is generally in qualitative agreement with the previous estimate,quantitative discrepancy is found to exist.According to current statistics, the tropical easterlies carry water vapor of 0.43 Sv from the Atlantic basin across Central America into the Pacific,and the northern westerlies allow water vapor of 0.25 Sv to escape from the Pacific. Quantitative analyses also reveal that the seasonal variation of net zonal vapor flux for the Pacific and the Indian Oceans is stronger than that for the Atlantic,which may be favorable for the maintenance of high salinity feature of the Atlantic Ocean.展开更多
A three-dimensional variational method is proposed to simultaneously retrieve the 3-D atmospheric temperature and moisture profiles from satellite radiance measurements. To include both vertical structure and the hori...A three-dimensional variational method is proposed to simultaneously retrieve the 3-D atmospheric temperature and moisture profiles from satellite radiance measurements. To include both vertical structure and the horizontal patterns of the atmospheric temperature and moisture, an EOF technique is used to decompose the temperature and moisture field in a 3-D space. A number of numerical simulations are conducted and they demonstrate that the 3-D method is less sensitive to the observation errors compared to the 1-D method. When the observation error is more than 2.0 K, to get the best results, the truncation number for the EOF＇s expansion have to be restricted to 2 in the 1-D method, while it can be set as large as 40 in a 3-D method. This results in the truncation error being reduced and the retrieval accuracy being improved in the 3-D method. Compared to the 1-D method, the rms errors of the 3-D method are reduced by 48% and 36% for the temperature and moisture retrievals, respectively. Using the real satellite measured brightness temperatures at 0557 UTC 31 July 2002, the temperature and moisture profiles are retrieved over a region （20°-45°N, 100°- 125°E） and compared with 37 collocated radiosonde observations. The results show that the retrieval accuracy with a 3-D method is significantly higher than those with the 1-D method.展开更多
Poleward atmospheric moisture transport(AMT) into the Arctic Ocean can change atmospheric moisture or water vapor content and cause cloud formation and redistribution, which may change downward longwave radiation and,...Poleward atmospheric moisture transport(AMT) into the Arctic Ocean can change atmospheric moisture or water vapor content and cause cloud formation and redistribution, which may change downward longwave radiation and, in turn, surface energy budgets, air temperatures, and sea-ice production and melt. In this study, we found a consistently enhanced poleward AMT across 60?N since 1959 based on the NCAR–NCEP reanalysis. Regional analysis demonstrates that the poleward AMT predominantly occurs over the North Atlantic and North Pacific regions, contributing about 57% and 32%, respectively, to the total transport. To improve our understanding of the driving force for this enhanced poleward AMT, we explored the role that extratropical cyclone activity may play. Climatologically, about 207 extratropical cyclones move across 60?N into the Arctic Ocean each year, among which about 66(32% of the total) and 47(23%) originate from the North Atlantic and North Pacific Ocean, respectively. When analyzing the linear trends of the time series constructed by using a 20-year running window, we found a positive correlation of 0.70 between poleward yearly AMT and the integrated cyclone activity index(measurement of cyclone intensity, number, and duration). This shows the consistent multidecadal changes between these two parameters and may suggest cyclone activity plays a driving role in the enhanced poleward AMT. Furthermore, a composite analysis indicates that intensification and poleward extension of the Icelandic low and accompanying strengthened cyclone activity play an important role in enhancing poleward AMT over the North Atlantic region.展开更多
Atmospheric moisture exploitation is emerging as a promising alternative to relieve the shortage of freshwater and energy.Efforts to exploit hygroscopic materials featuring flexibility,programmability,and accessibilit...Atmospheric moisture exploitation is emerging as a promising alternative to relieve the shortage of freshwater and energy.Efforts to exploit hygroscopic materials featuring flexibility,programmability,and accessibility are crucial to portable and adaptable devices.However,current two-dimensional(2D)or three-dimensional(3D)-based hygroscopic materials are dif-ficult to adapt to diverse irregular surfaces and meet breathability,which severely hinders their wide applications in wearable and programmable devices.Herein,hygroscopic organogel fibers(HOGFs)were designed via a wet-spinning strategy.The achieved fibers were composed of the hydrophilic polymeric network,hygroscopic solvent,and photothermal/antibacterial Ag nanoparticles(AgNPs),enabling hygroscopic capacity,photothermal conversion,and antibacterial.Owing to the good knittable feature,the HOGFs can be readily woven to adjusted 2D textiles to function as an efficient self-sustained solar evaporator of 4-layer woven HOGF device with a saturated moisture capacity of 1.63 kg m^(-2) and water-releasing rate of 1.46 kg m^(-2) h^(-1).Furthermore,the 2D textile can be applied as a wearable dehumidification device to efficiently remove the evaporative moisture from human skin to maintain a comfortable environment.It can reduce the humidity from 90 to 33.4%within 12.5 min.In addition,the introduction of AgNPs can also endow the HOGFs with antibacterial features,demonstrat-ing significant potential in personal healthcare.展开更多
Based on the concept of cloud water resource(CWR)and the cloud microphysical scheme developed by the Chinese Academy of Meteorological Sciences(CAMS),a coupled mesoscale and cloud-resolving model system is developed i...Based on the concept of cloud water resource(CWR)and the cloud microphysical scheme developed by the Chinese Academy of Meteorological Sciences(CAMS),a coupled mesoscale and cloud-resolving model system is developed in the study for CWR numerical quantification(CWR-NQ)in North China for 2017.The results show that(1)the model system is stable and capable for performing 1-yr continuous simulation with a water budget error of less than 0.2%,which indicates a good water balance.(2)Compared with the observational data,it is confirmed that the simulating capability of the CWR-NQ approach is decent for the spatial distribution of yearly cumulative precipitation,daily precipitation intensity,yearly average spatial distribution of water vapor.(3)Compared with the CWR diagnostic quantification(CWR-DQ),the results from the CWR-NQ differ mainly in cloud condensation and cloud evaporation.However,the deviation of the net condensation(condensation minus evaporation)between the two methods is less than 1%.For other composition variables,such as water vapor advection,surface evaporation,precipitation,cloud condensation,and total atmospheric water substances,the relative differences between the CWR-NQ and the CWR-DQ are less than 5%.(4)The spatiotemporal features of the CWR in North China are also studied.The positive correlation between water vapor convergence and precipitation on monthly and seasonal scales,and the lag of precipitation relative to water vapor convergence on hourly and daily scales are analyzed in detail,indicating the significance of the state term on hourly and daily scales.The effects of different spatial scales on the state term,advection term,source-sink term,and total amount are analyzed.It is shown that the advective term varies greatly at different spatiotemporal scales,which leads to differences at different spatiotemporal scales in CWR and related characteristic quantities.展开更多
基金The Global Change Research Program of China under contract No.2015CB953902the National Natural Science Foundation of China under contract Nos 41376008,41330960 and 41576020。
文摘Atmospheric moisture transport plays an important role in latent heat release and hydrologic interactions in the Arctic.In recent years,with the rapid decline in sea ice,this transport has changed.Here,we calculated the vertically integrated atmospheric moisture meridional transport(AMTv)from two global reanalysis datasets,from1979–2015,and found moisture pathways into the central Arctic.Four stable pathways showed an occurrence frequency greater than 70%,and these pathways exhibited a perennial seasonal pattern in the atmosphere above the Laptev Sea Pathway(LSP),Canadian Arctic Archipelago Pathway(CAAP),both sides of the Greenland plateau.Another seasonal pathway appeared above the east of the Chukchi Sea(CSP)during the melting/freezing months(March to September).Through these pathways,AMTv contributed a total moisture exchange of60%–80%—averaged over a 75°N circle—and focused on the low troposphere.Transports across the LSP,CSP and CAAP pathways likely create an enclosed moisture route.Meridional moisture fluxes are intensified in the Pacific sector of Arctic(PSA),especially during melting/freezing months.AMTv interannual variabilities are illustrated mainly in the Laptev Sea and the east Greenland pathway.Results indicate that accompanying a tendency for a stronger Beaufort Sea High in this sea level pressure field,AMTv through PSA pathways,switched from output to input,and approximately 960 km^3 of equivalent liquid water was transferred into the central Arctic during each decade.The detrended AMTv increment is highly correlated with the rapid decline of old ice areas(correlation coefficient is–0.78)for their synchronous fluctuations in the 1980 s and the last decade.
基金the Key Project of"Studies on the Climate Variability over China and the Globe during the 20th Century"(No.49635190)National Natural Science Foundation of China and the"National Key Project-Studies on S
文摘With the objective of providing a relatively accurate and complete diagram,the global scale interbasin transport of atmospheric moisture on the basis of the NCEP/NCAR reanalysis data for the period 1980 to 1994 is evaluated.The results show that the net zonal vapor flux for the Pacific,the Atlantic and the Indian Oceans is 0.25 Sv,—0.68 Sv and —0.29 Sv respectively.The marking differences in the zonal moisture budget among individual basins are speculated as the reason that dominates the differences in the salinity between the Pacific and the Atlantic Oceans.Though current evaluation on the net zonal moisture flux for the Atlantic basin is generally in qualitative agreement with the previous estimate,quantitative discrepancy is found to exist.According to current statistics, the tropical easterlies carry water vapor of 0.43 Sv from the Atlantic basin across Central America into the Pacific,and the northern westerlies allow water vapor of 0.25 Sv to escape from the Pacific. Quantitative analyses also reveal that the seasonal variation of net zonal vapor flux for the Pacific and the Indian Oceans is stronger than that for the Atlantic,which may be favorable for the maintenance of high salinity feature of the Atlantic Ocean.
基金the 973 Program (Grant No. 2004CB418305)the National Natural Science Foundation of China(Grant No. 40575049).
文摘A three-dimensional variational method is proposed to simultaneously retrieve the 3-D atmospheric temperature and moisture profiles from satellite radiance measurements. To include both vertical structure and the horizontal patterns of the atmospheric temperature and moisture, an EOF technique is used to decompose the temperature and moisture field in a 3-D space. A number of numerical simulations are conducted and they demonstrate that the 3-D method is less sensitive to the observation errors compared to the 1-D method. When the observation error is more than 2.0 K, to get the best results, the truncation number for the EOF＇s expansion have to be restricted to 2 in the 1-D method, while it can be set as large as 40 in a 3-D method. This results in the truncation error being reduced and the retrieval accuracy being improved in the 3-D method. Compared to the 1-D method, the rms errors of the 3-D method are reduced by 48% and 36% for the temperature and moisture retrievals, respectively. Using the real satellite measured brightness temperatures at 0557 UTC 31 July 2002, the temperature and moisture profiles are retrieved over a region （20°-45°N, 100°- 125°E） and compared with 37 collocated radiosonde observations. The results show that the retrieval accuracy with a 3-D method is significantly higher than those with the 1-D method.
基金This work was supported by the NSF(Grant Nos.ARC1023592,ARC-1107509,and PLR-1304684)
文摘Poleward atmospheric moisture transport(AMT) into the Arctic Ocean can change atmospheric moisture or water vapor content and cause cloud formation and redistribution, which may change downward longwave radiation and, in turn, surface energy budgets, air temperatures, and sea-ice production and melt. In this study, we found a consistently enhanced poleward AMT across 60?N since 1959 based on the NCAR–NCEP reanalysis. Regional analysis demonstrates that the poleward AMT predominantly occurs over the North Atlantic and North Pacific regions, contributing about 57% and 32%, respectively, to the total transport. To improve our understanding of the driving force for this enhanced poleward AMT, we explored the role that extratropical cyclone activity may play. Climatologically, about 207 extratropical cyclones move across 60?N into the Arctic Ocean each year, among which about 66(32% of the total) and 47(23%) originate from the North Atlantic and North Pacific Ocean, respectively. When analyzing the linear trends of the time series constructed by using a 20-year running window, we found a positive correlation of 0.70 between poleward yearly AMT and the integrated cyclone activity index(measurement of cyclone intensity, number, and duration). This shows the consistent multidecadal changes between these two parameters and may suggest cyclone activity plays a driving role in the enhanced poleward AMT. Furthermore, a composite analysis indicates that intensification and poleward extension of the Icelandic low and accompanying strengthened cyclone activity play an important role in enhancing poleward AMT over the North Atlantic region.
基金supported by the Natural Science Foundation of China(52073295)Ningbo Science and Technology Bureau(2021Z127)+4 种基金Ningbo Public Welfare Science and Technology Plan Project(2021S150)The Sino-German Mobility Program(M-0424)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDB-SSW-SLH036)Bureau of International Cooperation,Chinese Academy of Sciences(174433KYSB20170061)K.C.Wong Education Foundation(GJTD-2019-13).
文摘Atmospheric moisture exploitation is emerging as a promising alternative to relieve the shortage of freshwater and energy.Efforts to exploit hygroscopic materials featuring flexibility,programmability,and accessibility are crucial to portable and adaptable devices.However,current two-dimensional(2D)or three-dimensional(3D)-based hygroscopic materials are dif-ficult to adapt to diverse irregular surfaces and meet breathability,which severely hinders their wide applications in wearable and programmable devices.Herein,hygroscopic organogel fibers(HOGFs)were designed via a wet-spinning strategy.The achieved fibers were composed of the hydrophilic polymeric network,hygroscopic solvent,and photothermal/antibacterial Ag nanoparticles(AgNPs),enabling hygroscopic capacity,photothermal conversion,and antibacterial.Owing to the good knittable feature,the HOGFs can be readily woven to adjusted 2D textiles to function as an efficient self-sustained solar evaporator of 4-layer woven HOGF device with a saturated moisture capacity of 1.63 kg m^(-2) and water-releasing rate of 1.46 kg m^(-2) h^(-1).Furthermore,the 2D textile can be applied as a wearable dehumidification device to efficiently remove the evaporative moisture from human skin to maintain a comfortable environment.It can reduce the humidity from 90 to 33.4%within 12.5 min.In addition,the introduction of AgNPs can also endow the HOGFs with antibacterial features,demonstrat-ing significant potential in personal healthcare.
基金Supported by the National Key Research and Development Program of China(2016YFA0601701)National Natural Science Foundation of China(42075191)National High Technology Research and Development Program of China(2012AA120902).
文摘Based on the concept of cloud water resource(CWR)and the cloud microphysical scheme developed by the Chinese Academy of Meteorological Sciences(CAMS),a coupled mesoscale and cloud-resolving model system is developed in the study for CWR numerical quantification(CWR-NQ)in North China for 2017.The results show that(1)the model system is stable and capable for performing 1-yr continuous simulation with a water budget error of less than 0.2%,which indicates a good water balance.(2)Compared with the observational data,it is confirmed that the simulating capability of the CWR-NQ approach is decent for the spatial distribution of yearly cumulative precipitation,daily precipitation intensity,yearly average spatial distribution of water vapor.(3)Compared with the CWR diagnostic quantification(CWR-DQ),the results from the CWR-NQ differ mainly in cloud condensation and cloud evaporation.However,the deviation of the net condensation(condensation minus evaporation)between the two methods is less than 1%.For other composition variables,such as water vapor advection,surface evaporation,precipitation,cloud condensation,and total atmospheric water substances,the relative differences between the CWR-NQ and the CWR-DQ are less than 5%.(4)The spatiotemporal features of the CWR in North China are also studied.The positive correlation between water vapor convergence and precipitation on monthly and seasonal scales,and the lag of precipitation relative to water vapor convergence on hourly and daily scales are analyzed in detail,indicating the significance of the state term on hourly and daily scales.The effects of different spatial scales on the state term,advection term,source-sink term,and total amount are analyzed.It is shown that the advective term varies greatly at different spatiotemporal scales,which leads to differences at different spatiotemporal scales in CWR and related characteristic quantities.
