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The response of the upper ocean to tropical cyclone Viyaru over the Bay of Bengal 预览
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作者 Mir Kashem Md Kawser Ahmed +2 位作者 Fangli Qiao M A E Akhter K M Azam Chowdhury 《海洋学报:英文版》 SCIE CAS CSCD 2019年第1期61-70,共10页
Better forecast of tropical cyclone (TC) can help to reduce risk and enhance management. The TC forecast depends on the scientific understanding of oceanic processes, air-sea interaction and finally, the atmospheric p... Better forecast of tropical cyclone (TC) can help to reduce risk and enhance management. The TC forecast depends on the scientific understanding of oceanic processes, air-sea interaction and finally, the atmospheric process. The TC Viyaru is taken as an example, which is formed at the end of 11 May 2013 and sustains up to 17 May 2013 during pre-monsoon season. Argo data are used to investigate ocean response processes by comparing pre- and post-conditions of the TC. Eight oceanic parameters including the sea surface temperature (SST), the sea surface salinity (SSS), and the barrier layer thickness (BLT), the 26℃ isotherm depth in the ocean (D26), the isothermal layer depth (ILD), the mixed layer depth (MLD), the tropical cyclone heat potential (TCHP) and the effective oceanic layer for cyclogenesis (EOLC) are chosen to evaluate the pre- and post-conditions of the TC along the track of Viyaru. The values of the SST, D26, BLT, TCHP and EOLC in the pre-cyclonic condition are higher than the post-cyclonic condition, while the SSS, ILD and MLD in the post-cyclonic condition are higher than the pre-cyclonic condition of the ocean due to strong cyclonic winds and subsurface upwelling. It is interesting that the strong intensity of the TC reduces less SST and vice versa. The satisfied real time Argo data is not available in the northern Bay of Bengal especially in the coastal region. A weather research and forecasting model is employed to hindcast the track of Viyaru, and the satellite data from the National Center Environmental Prediction are used to assess the hindcast. 展开更多
关键词 effective OCEANIC layer for cyclogenesis sea surface temperature TROPICAL CYCLONE TROPICAL CYCLONE heat potential TROPICAL CYCLONE viyaru WEATHER research and forecasting model
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Impacts of Soil Moisture on the Numerical Simulation of a Post-Landfall Storm
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作者 Feimin ZHANG Zhaoxia PU Chenghai WANG 《气象学报:英文版》 SCIE CSCD 2019年第2期206-218,共13页
Surface heat and moisture fluxes are important to the evolution of a tropical storm after its landfall. Soil moisture is one of the essential components that influence surface heating and moisture fluxes. In this stud... Surface heat and moisture fluxes are important to the evolution of a tropical storm after its landfall. Soil moisture is one of the essential components that influence surface heating and moisture fluxes. In this study, the impact of soil moisture on a pre-landfall numerical simulation of Tropical Storm Bill(2015), which had a much longer lifespan over land, is investigated by using the research version of the NCEP Hurricane Weather Research and Forecasting(HWRF) model. It is found that increased soil moisture with SLAB scheme before storm’s landfall tends to produce a weaker storm after landfall and has negative impacts on storm track simulation. Further diagnoses with different land surface schemes and sensitivity experiments indicate that the increase in soil moisture inside the storm corresponds to a strengthened vertical mixing within the storm boundary layer, which is conducive to the decay of storm and has negative impacts on storm evolution. In addition, surface diabatic heating effects over the storm environment are also found to be an important positive contribution to the storm evolution over land, but their impacts are not so substantial as boundary layer vertical mixing inside the storm. The overall results highlight the importance and uncertainty of soil moisture in numerical model simulations of landfalling hurricanes and their further evolution over land. 展开更多
关键词 soil moisture TROPICAL STORM TROPICAL CYCLONE LANDFALL la nd surface numerical simulation
Trophic functioning of macrobenthic fauna in a tropical acidified Bornean estuary(Southeast Asia) 预览
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作者 Mohammad Belal Hossain 《国际泥沙研究:英文版》 SCIE 2019年第1期48-57,共10页
The trophic structure of a community is used to infer ecosystem functioning(e.g.energy transfer and nutrient cycling).Here the trophic structure of the benthic infaunal and epifaunal communities in the Brunei Estuary ... The trophic structure of a community is used to infer ecosystem functioning(e.g.energy transfer and nutrient cycling).Here the trophic structure of the benthic infaunal and epifaunal communities in the Brunei Estuary are characterized,and their distribution along an estuarine pH gradient is analyzed using univariate and multivariate techniques.This analysis revealed that surface deposit feeders(e.g.,polychaetes)were numerically dominant within the infaunal communities whereas in the epifaunal communities filter feeders(e.g.,bivalves)were highly abundant.Species richness for almost all trophic groups increased toward the lower estuary,except for omnivores in the epifaunal communities,which decreased markedly.Both Analysis of Variance(ANOVA)and Analysis of Similarities(ANOSIM)detected significant differences in the density of respective trophic groups among stations.Within infaunal communities,both Biological and Environmental procedure(BIO-ENV)and Canonical Correspondence Analysis(CCA)showed that trophic shifts were associated with environmental gradients.Surface-deposit feeders and omnivores were the most abundant macrobenthos of the upper estuary characterized by low salinity,low pH,and a higher percentage of mud particles.The proportion of filter feeders and carnivores increased with salinity/pH and sand.A more uniform distribution of trophic structure was found in the lower estuary,with high salinity and pH over sandy habitat.In contrast,within epifaunal trophic groups,the percentage of surface deposit feeders and omnivores declined,but filter feeders remarkably increased toward the sea.The proportion of carnivores remained similar at all stations.Non-Metric Multidimensional Scaling(nMDS)ordination for epifaunal trophic groups clearly demarcated higher salinity/pH stations from lower salinity/pH stations,suggesting different trophic compositions along the estuarine pH gradient. 展开更多
关键词 Macrobenthic COMMUNITIES TROPHIC structure Environmental factors ACIDITY TROPICAL ESTUARY
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Oceanic barrier layer variation induced by tropical cyclones in the Northwest Pacific 预览
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作者 ZHANG Zhixiang LIU Lingling WANG Fan 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第2期375-384,共10页
According to Argo profiles and one-dimensional Price-Weller-Pinkel models, the oceanic barrier layer variation induced by tropical cyclones is adequately analyzed in the Northwest Pacific. Results show that tropical c... According to Argo profiles and one-dimensional Price-Weller-Pinkel models, the oceanic barrier layer variation induced by tropical cyclones is adequately analyzed in the Northwest Pacific. Results show that tropical cyclones mainly aff ect the oceanic barrier layer through intensifying and weakening pre-existed barrier layer. The former even may generate new one after tropical cyclones’ passage. The latter can make pre-existed one disappear. Local wind stress and precipitation, the dominant factors, primarily determine the variation of barrier layer. Negative eff ects of wind mainly focus on the north of 20°N. This phenomenon is more meaningful for slow tropical cyclones. Conversely, positive eff ects of wind and precipitation center on the south of 20°N in the Northwest Pacific. Some data indicate that the barrier layer variation is also closely related with initial mixed layer depth and barrier layer thickness. 展开更多
关键词 OCEANIC barrier layer tropical CYCLONES NORTHWEST PACIFIC ARGO Price-Weller-Pinkel model
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Land cover changes and fragmentation in mountain neotropical ecosystems of Oaxaca,Mexico under community forest management 预览
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作者 Rafael M^a Navarro Cerrillo Dennis J.Esteves Vieira +2 位作者 Susana Ochoa-Gaona Bernardus H.J.de Jong M^a del Mar Delgado Serrano 《林业研究:英文版》 CAS CSCD 2019年第1期143-155,共13页
Changes in land cover have a direct impact on forest ecosystem goods and services.In this study,changes in land cover in Sierra de Juarez–Oaxaca ecosystems were estimated using a consistent processing of Landsat imag... Changes in land cover have a direct impact on forest ecosystem goods and services.In this study,changes in land cover in Sierra de Juarez–Oaxaca ecosystems were estimated using a consistent processing of Landsat images and OBIA methodology.Additionally,landscape analyses using FRAGSTAT were conducted.In 2014,Sierra de Juarez–Oaxaca was covered by approximately 84% of forests,mainly pine-oak and cloud forests.After extensive deforestation until 2001,this trend was reversed and the forest cover surface area in 2014 was slightly higher than in 1979.The comparison of the landscape structure of the forested and agricultural lands suggests an increase in habitat heterogeneity.However,interspersion and juxtaposition indices,showing the patch shape by patch area and perimeter,were similar throughout the study period(1979–2014).Social and economic drivers can explain this situation:namely,community organization,forest enterprises,payment for ecosystem services programs,and changes of agricultural activity.Communities in the Sierra of Oaxaca have reforested degraded lands,created community forest enterprises,and preserved the forest under conservation schemes like those proposed by the Mexican payment for ecosystem services programs.However,their sustainable management faces internal challenges and has become highly dependent on political and institutional decisions beyond their control. 展开更多
关键词 Tropical and TEMPERATE FORESTS Social forestry Land uses segmentation OBIA FRAGSTAT
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QUASI STEADY-STATE HURRICANES REVISITED
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作者 JOHN PERSING MICHAEL T.MONTGOMERY +1 位作者 ROGER K.SMITH JAMES C.MCWILLIAMS 《热带气旋研究与评论(英文版)》 2019年第1期1-17,共17页
We revisit the theoretical possibility of long-term, sustained tropical cyclone solutions using a state-of-the-art numerical model that incorporates the most recent observational guidance for subgrid scale parameters ... We revisit the theoretical possibility of long-term, sustained tropical cyclone solutions using a state-of-the-art numerical model that incorporates the most recent observational guidance for subgrid scale parameters and airsea exchange coefficients of heat and momentum. Emphasis is placed on the realism of such solutions and the sources of cyclonic relative angular momentum(RAM) that are necessary to replenish that lost by friction at the surface. For simplicity, we confine our attention to strictly axisymmetric numerical experiments.We are able to replicate Hakim’s long-term simulation of a quasi-steady state cyclone in a 1500 km radial domain. The structure of the wind field is found to be somewhat realistic compared to observations, but sustained by unrealistic processes. Artificial sources of cyclonic RAM are quantified and the lateral damping of the anticyclonic wind near the outer boundary is found to make the largest contribution to the source of cyclonic RAM. When the domain size is extended to 9,000 km radius and lateral damping is removed altogether, a quasi-steady vortex emerges, but the structure of this vortex has many unrealistic features. In this solution, the remaining upper-level Rayleigh damping contributes a major portion of the needed source of cyclonic RAM. In a simulation in which the upper-level damping is removed also, the solution is found to be neither quasi-steady nor realistic.These findings call into question the realism of long-term, sustained tropical cyclone simulations, which require a sufficiently large source of cyclonic RAM to facilitate the existence of a quasi-steady state. 展开更多
关键词 TROPICAL CYCLONES STEADY-STATE ANGULAR MOMENTUM
Biomass increment and mortality losses in tropical secondary forests of Hainan,China 预览
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作者 Junfu Zhao Chunsheng He +6 位作者 Chunlin Qi Xu Wang Haiyan Deng Chunxin Wang Haiwei Liu Lianyan Yang Zhenghong Tan 《林业研究:英文版》 CAS CSCD 2019年第2期647-655,共9页
Secondary forests,created after heavy logging,are an important part of China’s forests.We investigated forest biomass and its accumulation rate in 38 plots in a tropical secondary forest on Hainan Island.These second... Secondary forests,created after heavy logging,are an important part of China’s forests.We investigated forest biomass and its accumulation rate in 38 plots in a tropical secondary forest on Hainan Island.These secondary forests are moderate carbon sinks,averaging 1.96–2.17 t C ha^-1 a^-1.Biomass increment is largely by medium-sized(10–35 m)trees.Tree mortality accounts for almost 30%of the biomass and plays a negligible role in biomass accumulation estimates.Mortality rate is highly dependent on tree size.For small trees and seedlings,it is related to competition due to elevated irradiance after logging.Regarding prospective biomass and rates of accumulation,recovery is not as rapid as in secondary forests of cleared land.Therefore,tropical forests are susceptible to logging operations and need careful forest management. 展开更多
关键词 Tropical secondary forest management Carbon SINK Inventory Dynamic PLOT LOGGING
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Soil Metagenome of Tropical White Sand Heath Forests in Borneo:What Functional Traits Are Associated with an Extreme Environment Within the Tropical Rainforest?
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作者 Dorsaf KERFAHI Binu M.TRIPATHI +6 位作者 Johan W.Ferry SLIK Rahayu S.SUKRI Salwana JAAFAR Ke DONG Matthew Chidozie OGWU Hyo-Ki KIM Jonathan M.ADAMS 《土壤圈:英文版》 SCIE CAS CSCD 2019年第1期12-23,共12页
White sand heath forests(WS) or kerangas, an unusual variant of tropical forests in Borneo, characterized by open scrubby vegetation, low productivity, and distinctive plant species composition and soil microbial comm... White sand heath forests(WS) or kerangas, an unusual variant of tropical forests in Borneo, characterized by open scrubby vegetation, low productivity, and distinctive plant species composition and soil microbial community, are regarded as a stressful lowpH and/or nutrient environment. We investigated whether the functional soil metagenome also shows a predicted set of indicators of stressful conditions in WS. Based on stress-tolerant strategies exhibited by larger organisms, we hypothesized that genes for stress tolerance, dormancy, sporulation, and nutrient processing are more abundant in the soil microbiota of WS. We also hypothesized that there is less evidence of biotic interaction in white sand soils, with lower connectivity and fewer genes related to organismic interactions. In Brunei, we sampled soils from a WS and a normal primary dipterocarp forest, together with an inland heath, an intermediate forest type. Soil DNA was extracted, and shotgun sequencing was performed using Illumina HiSeq platform, with classification by the Metagenomics Rapid Annotation using Subsystem Technology(MG-RAST). The results, on one hand, supported our hypothesis(on greater abundance of dormancy, virulence, and sporulation-related genes). However, some aspects of our results showed no significant difference(specifically in stress tolerance, antibiotic resistance, viruses, and clustered regularly interspaced short palindrome repeats(CRISPRs)). It appears that in certain respects, the extreme white sand environment produces the predicted strategy of less biotic interaction, but exhibits high soil microbiota connectivity and functional diversity. 展开更多
关键词 antibiotic resistance biotic interaction kerangas microbial community MICROBIOTA SHOTGUN METAGENOMICS stress tolerance TROPICAL forest
Sea-Salt Aerosol Effects on the Simulated Microphysics and Precipitation in a Tropical Cyclone
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作者 Baolin JIANG Wenshi LIN +1 位作者 Fangzhou LI Junwen CHEN 《气象学报:英文版》 SCIE CSCD 2019年第1期115-125,共11页
We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecast... We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem) was used together with a parameterization of SSA production. Three simulations, with different levels of SSA emission(CTL, LOW, HIGH), were conducted. The simulation results show that SSA contributes to the processes of autoconversion of cloud water and accretion of cloud water by rain,thereby promoting rain formation. The latent heat release increases with SSA emission, slightly increasing horizontal wind speeds of the TC. The presence of SSA also regulates the thermodynamic structure and precipitation of the TC.In the HIGH simulation, higher latent heat release gives rise to stronger updrafts in the TC eyewall area, leading to enhanced precipitation. In the LOW simulation, due to decreased latent heat release, the temperature in the TC eye is lower, enhancing the downdrafts in the region;and because of conservation of mass, updrafts in the eyewall also strengthen slightly;as a result, precipitation in the LOW experiment is a little higher than that in the CTL experiment.Overall, the relationship between the precipitation rate and SSA emission is nonlinear. 展开更多
关键词 SEA-SALT aerosol MICROPHYSICS tropical CYCLONE WRF-Chem cloud CONDENSATION NUCLEI
Importance of identifying tropical cyclone tornadoes in typhoon warning and defense systems
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作者 Dan Yao Xudong Liang +5 位作者 Qing Meng Jian Li Chong Wu Zhengshuai Xie Dandan Chen Jianping Guo 《科学通报:英文版》 SCIE EI CSCD 2019年第3期143-145,共3页
Tornadoes are highly localized severe weather phenomena and have been of increasing concern in China [1] in recent years, especially after the sinking of the Oriental Star in 2015 [2] and severe tornado damage in Yanc... Tornadoes are highly localized severe weather phenomena and have been of increasing concern in China [1] in recent years, especially after the sinking of the Oriental Star in 2015 [2] and severe tornado damage in Yancheng in 2016 (3)Tornadoes induced by tropical cyclones, however, have received little attention.A recent study has shown that a large number of tornado-scale vortices can be produced at the inner edge of the intense eyewallconvection of tropical cyclones [4]. 展开更多
关键词 TROPICAL CYCLONE defense systems UAV LST
Spatial Downscaling of the Tropical Rainfall Measuring Mission Precipitation Using Geographically Weighted Regression Kriging over the Lancang River Basin, China 预览
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作者 LI Yungang ZHANG Yueyuan +2 位作者 HE Daming LUO Xian JI Xuan 《中国地理科学:英文版》 SCIE CSCD 2019年第3期446-462,共17页
Satellite-based precipitation products have been widely used to estimate precipitation, especially over regions with sparse rain gauge networks. However, the low spatial resolution of these products has limited their ... Satellite-based precipitation products have been widely used to estimate precipitation, especially over regions with sparse rain gauge networks. However, the low spatial resolution of these products has limited their application in localized regions and watersheds.This study investigated a spatial downscaling approach, Geographically Weighted Regression Kriging(GWRK), to downscale the Tropical Rainfall Measuring Mission(TRMM) 3 B43 Version 7 over the Lancang River Basin(LRB) for 2001–2015. Downscaling was performed based on the relationships between the TRMM precipitation and the Normalized Difference Vegetation Index(NDVI), the Land Surface Temperature(LST), and the Digital Elevation Model(DEM). Geographical ratio analysis(GRA) was used to calibrate the annual downscaled precipitation data, and the monthly fractions derived from the original TRMM data were used to disaggregate annual downscaled and calibrated precipitation to monthly precipitation at 1 km resolution. The final downscaled precipitation datasets were validated against station-based observed precipitation in 2001–2015. Results showed that: 1) The TRMM 3 B43 precipitation was highly accurate with slight overestimation at the basin scale(i.e., CC(correlation coefficient) = 0.91, Bias = 13.3%). Spatially, the accuracies of the upstream and downstream regions were higher than that of the midstream region. 2) The annual downscaled TRMM precipitation data at 1 km spatial resolution obtained by GWRK effectively captured the high spatial variability of precipitation over the LRB. 3) The annual downscaled TRMM precipitation with GRA calibration gave better accuracy compared with the original TRMM dataset. 4) The final downscaled and calibrated precipitation had significantly improved spatial resolution, and agreed well with data from the validated rain gauge stations, i.e., CC = 0.75, RMSE(root mean square error) = 182 mm, MAE(mean absolute error) = 142 mm, and Bias = 0.78%for annual precipitation and CC = 0.95, RMSE = 25 mm, MAE = 16 mm, and Bias = 0.6 展开更多
关键词 PRECIPITATION Tropical Rainfall Measuring Mission(TRMM) 3B43 Geographically Weighted Regression Kriging(GWRK) SPATIAL DOWNSCALING the Lancang River Basin China
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Post-fire soil nutrient dynamics in a tropical dry deciduous forest of Western Ghats,India 预览
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作者 Satyam Verma Dharmatma Singh +1 位作者 Ajeet Kumar Singh Shanmuganathan Jayakumar 《森林生态系统:英文版》 CSCD 2019年第1期67-75,共9页
Background: The effect of forest fire on soil is complex and relatively less understood than its above ground effect.Understanding the effect of fire on forest soils can allow improving management of valuable forest e... Background: The effect of forest fire on soil is complex and relatively less understood than its above ground effect.Understanding the effect of fire on forest soils can allow improving management of valuable forest ecosystems as adequate and proper information is very important for efficient management. We have studied the recovery of soil properties after fire, using a chronosequence approach(two, five and fifteen years after fire and control). Soil samples were collected from each plot of four fire patches(B0, B2, B5 & B15) from three different depths viz. 0–10(Top), 10–20(Middle), and 20–30 cm(Bottom).Results: Soil organic carbon was lower than unburned plots after the fire and could not recover to the level of unburned plot(B0) even in 15 years. Total N, available P, and extractable K were lower 2-years and 5-years after the fire but are higher than unburned plot after 15-years. Available nitrogen(NO3^- and NH4^+) remain unchanged or higher than B0 in burned patches. Soil pH, Bulk Density, Water Holding Capacity, and Electrical Conductivity was lower initially after the fire. Forest fires have affected soil properties considerably. The response of soil properties varied with years after fire and soil depth.Conclusion: Forest fires occur very frequently in the study area. Significant quantities of carbon and total nitrogen are lost to the atmosphere by burning of litter, duff, and soil OM. Because nitrogen is one of the most important soil nutrients, the recapture of N lost by volatilization during a fire must receive special attention. Long-term studies are required to better understand the recovery of soil nitrogen. 展开更多
关键词 Soil properties Western Ghats TROPICAL DRY DECIDUOUS FOREST FOREST fire FOREST SOILS
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Ensemble Forecasts of Tropical Cyclone Track with Orthogonal Conditional Nonlinear Optimal Perturbations 预览
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作者 Zhenhua HUO Wansuo DUAN Feifan ZHOU 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第2期231-247,共17页
This paper preliminarily investigates the application of the orthogonal conditional nonlinear optimal perturbations(CNOPs)–based ensemble forecast technique in MM5(Fifth-generation Pennsylvania State University–Nati... This paper preliminarily investigates the application of the orthogonal conditional nonlinear optimal perturbations(CNOPs)–based ensemble forecast technique in MM5(Fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model).The results show that the ensemble forecast members generated by the orthogonal CNOPs present large spreads but tend to be located on the two sides of real tropical cyclone(TC)tracks and have good agreements between ensemble spreads and ensemble-mean forecast errors for TC tracks.Subsequently,these members reflect more reasonable forecast uncertainties and enhance the orthogonal CNOPs–based ensemble-mean forecasts to obtain higher skill for TC tracks than the orthogonal SVs(singular vectors)–,BVs(bred vectors)– and RPs(random perturbations)–based ones.The results indicate that orthogonal CNOPs of smaller magnitudes should be adopted to construct the initial ensemble perturbations for short lead–time forecasts,but those of larger magnitudes should be used for longer lead–time forecasts due to the effects of nonlinearities.The performance of the orthogonal CNOPs–based ensemble-mean forecasts is case-dependent,which encourages evaluating statistically the forecast skill with more TC cases.Finally,the results show that the ensemble forecasts with only initial perturbations in this work do not increase the forecast skill of TC intensity,which may be related with both the coarse model horizontal resolution and the model error. 展开更多
关键词 ENSEMBLE FORECAST initial PERTURBATION CONDITIONAL nonlinear optimal PERTURBATION tropical CYCLONE
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Interannual Salinity Variability in the Tropical Pacific in CMIP5 Simulations 预览
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作者 Hai ZHI Rong-Hua ZHANG +2 位作者 Pengfei LIN Peng YU Rong-Hua ZHANG 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第4期378-396,共19页
Salinity variability and its causes in the tropical Pacific are analyzed using observations,reanalysis products and model simulations.The mixed-layer salinity(MLS)budget analyses from observations and reanalysis produ... Salinity variability and its causes in the tropical Pacific are analyzed using observations,reanalysis products and model simulations.The mixed-layer salinity(MLS)budget analyses from observations and reanalysis products indicate that its interannual evolution is closely related to ENSO and is predominantly governed by surface forcing and surface advection in the western-central equatorial Pacific.It is found that the observed MLS tendency leads Ni?no3.4 by about 12 months due to the effect of negative freshwater flux(evaporation minus precipitation).These observation-based analyses are used to evaluate the corresponding simulation using GFDL-ESM2M.It is evident that the model can simulate the spatiotemporal variations of MLS with some discrepancies compared to observations.In the warm pool of the equatorial Pacific the MLS tendency in the model is sensitive to ocean dynamics,however model biases cause the tendency to be underestimated.In particular,the freshwater flux is overestimated while the ocean surface zonal current and vertical velocity at the base of the mixed layer are underestimated.Due to model biases in representing the related physics,the effects of surface forcing on the simulated MLS budget are overestimated and those of subsurface and surface advection are relatively weak.Due to weaker surface advection and subsurface forcing than observed,the simulated compensations for surface forcing are suppressed,and the simulated MLS tendency that leads Nino3.4 by 8–10 months,which is shorter than the observed lead time.These results are useful for the interpretation of observational analyses and other model simulations in the tropical Pacific. 展开更多
关键词 MIXED-LAYER SALINITY salt BUDGET INTERANNUAL VARIABILITY tropical Pacific model simulation
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Role of tropical cyclones over the western North Pacific in the East Asian summer monsoon system 预览
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作者 Xian Chen Zhong Zhong +3 位作者 YiJia Hu Shi Zhong Wei Lu Jing Jiang 《地球与行星物理:英文版》 CSCD 2019年第2期147-156,共10页
Precipitation observations collected at weather stations in eastern China,the NCEP/NCAR reanalysis data,the tropical cyclone(TC)Best Track Dataset,and a sensitivity numerical experiment were used in the present study ... Precipitation observations collected at weather stations in eastern China,the NCEP/NCAR reanalysis data,the tropical cyclone(TC)Best Track Dataset,and a sensitivity numerical experiment were used in the present study to investigate the role in the East Asian summer monsoon(EASM)system played by frequent TC activities over the western North Pacific(WNP).Results indicated that,in active TC years,the EASM is stronger and the southerly winds in the lower troposphere advance farther north and reach higher latitudes.Meanwhile,the monsoon rain belt remains in the lower and middle reaches of the Yangtze River valley for a relatively short period,leading to less precipitation there.Both the western Pacific subtropical high and the South Asian high weaken with the northward shift of the ridgelines for both high-pressure systems as well as the East Asian subtropical upper-level jet.Therefore,the impacts of frequent TC activities over the WNP on each individual component of the EASM are in phase with those of the stronger EASM itself,amplifying features of the already strengthened EASM. 展开更多
关键词 East Asian summer MONSOON TROPICAL CYCLONE western NORTH PACIFIC
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Surface Rainfall Processes during the Genesis Period of Tropical Cyclone Durian(2001) 预览
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作者 Yaping WANG Yongjie HUANG Xiaopeng CUI 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第4期451-464,共14页
The rainfall processes during the formation of tropical cyclone(TC)Durian(2001)were investigated quantitatively using the three-dimensional(3D)WRF-based precipitation equation.The rain rate(PS)decreased slightly as th... The rainfall processes during the formation of tropical cyclone(TC)Durian(2001)were investigated quantitatively using the three-dimensional(3D)WRF-based precipitation equation.The rain rate(PS)decreased slightly as the TC approached to formation,and then increased as Durian began to intensify.The rate of moisture-related processes(QWV)in the equation contributed around 80% to PS before TC genesis,and made more contribution during and after TC genesis.The rate of hydrometeor-related processes(QCM)contributed about 20% before TC formation,followed by less contribution during and after TC formation.QWV were dominated by the 3D moisture flux advection rate(QWVA),while the surface evaporation rate(QWVE)also played an important role.Just before TC genesis,moisture from QWVA and QWVE helped the local atmosphere moisten(negative QWVL).QCM were determined by the 3D hydrometeor advection rates(QCLA and QCIA)and the local change rates of hydrometeors(QCLL and QCIL).During TC formation,QCM largely decreased and then reactivated as Durian began to intensify,accompanied by the development of TC cloud.Both the height and the strength of the net latent heating center associated with microphysical processes generally lowered before and during TC genesis,resulting mainly from lessening deposition and condensation.The downward shift of the net latent heating center induced a more bottom-heavy upward mass flux profile,suggesting to promote lower-tropospheric convergence in a shallower layer,vorticity amplification and TC spin-up. 展开更多
关键词 SURFACE RAINFALL processes tropical CYCLONE formation three-dimensional precipitation equation LATENT heating
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Evidence of Specific MJO Phase Occurrence with Summertime California Central Valley Extreme Hot Weather 预览
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作者 Yun-Young LEE Richard GROTJAHN 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第6期589-602,共14页
This study examines associations between California Central Valley(CCV) heat waves and the Madden Julian Oscillation(MJO). These heat waves have major economic impact. Our prior work showed that CCV heat waves are fre... This study examines associations between California Central Valley(CCV) heat waves and the Madden Julian Oscillation(MJO). These heat waves have major economic impact. Our prior work showed that CCV heat waves are frequently preceded by convection over the tropical Indian and eastern Pacific oceans, in patterns identifiable with MJO phases. The main analysis method is lagged composites(formed after each MJO phase pair) of CCV synoptic station temperature, outgoing longwave radiation(OLR), and velocity potential(VP). Over the CCV, positive temperature anomalies occur only after the Indian Ocean(phases 2-3) or eastern Pacific Ocean(phases 8-1) convection(implied by OLR and VP fields). The largest fractions of CCV hot days occur in the two weeks after onset of those two phase pairs. OLR and VP composites have significant subsidence and convergence above divergence over the CCV during heat waves, and these structures are each part of larger patterns having significant areas over the Indian and Pacific Oceans. Prior studies showed that CCV heat waves can be roughly grouped into two clusters: Cluster 2 is preceded by a heat wave over northwestern North America, while Cluster 1 is not. OLR and VP composite analyses are applied separately to these two clusters. However, for Cluster 2, the subsidence and VP over the CCV are not significant, and the large-scale VP pattern has low correlation with the MJO lagged composite field. Therefore, the association between the MJO convection and subsequent CCV heat wave is more evident in Cluster 1 than Cluster 2. 展开更多
关键词 MJO heat wave large-scale METEOROLOGICAL pattern extratropical response TROPICAL CONVECTION
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热带园林4种木质藤本植物叶性状与环境适应能力研究 预览
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作者 王晓帆 冯嘉仪 +1 位作者 翁殊斐 秦昊林 《西南林业大学学报》 CAS 北大核心 2019年第3期166-171,共6页
为了探究不同木质藤本植物对环境变化的适应能力,以紫萼龙吐珠、狭叶异翅藤、蒜香藤和炮仗花4种常见的热带园林木质藤本植物为研究对象,通过测定叶片的10个性状,利用方差分析、主成分分析、模糊隶属函数分析探讨4种木质藤本植物对环境... 为了探究不同木质藤本植物对环境变化的适应能力,以紫萼龙吐珠、狭叶异翅藤、蒜香藤和炮仗花4种常见的热带园林木质藤本植物为研究对象,通过测定叶片的10个性状,利用方差分析、主成分分析、模糊隶属函数分析探讨4种木质藤本植物对环境适应能力的强弱。结果表明:紫萼龙吐珠的比叶体积、叶绿素a含量、叶绿素b含量和叶绿素含量均高于其他3种植物;在叶经济谱中,狭叶异翅藤、蒜香藤和炮仗花在资源轴上属于“快速投资收益”型物种,紫萼龙吐珠在资源轴上属于“缓慢投资收益”型物种;4种木质藤本植物的环境适应能力从强到弱分别为紫萼龙吐珠、炮仗花、蒜香藤、狭叶异翅藤。 展开更多
关键词 热带 藤本植物 性状 经济谱 环境 适应能力
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Causes of the Extreme Hot Midsummer in Central and South China during 2017:Role of the Western Tropical Pacific Warming 预览
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作者 Ruidan CHEN Zhiping WEN +1 位作者 Riyu LU Chunzai WANG 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第5期465-478,共14页
This study investigates why an extreme hot midsummer occurred in Central and South China(CSC)during 2017.It is shown that the western North Pacific subtropical high(WNPSH)was abnormally intensified and westward-extend... This study investigates why an extreme hot midsummer occurred in Central and South China(CSC)during 2017.It is shown that the western North Pacific subtropical high(WNPSH)was abnormally intensified and westward-extending,resulting in anomalous high pressure and consequent extreme heat over CSC.The abnormal WNPSH was favored by the warming of the western tropical Pacific(WTP),which was unrelated to ENSO and manifested its own individual e ect.The WTP warming enhanced the convection in-situ and led to anomalous high pressure over CSC via a local meridional circulation.The influence of the WTP was confirmed by CAM4 model experiments.A comparison between the 2017 midsummer and 2010 midsummer(with a stronger WNPSH but weaker extreme heat)indicated that the influence of the WNPSH on extreme heat can be modulated by the associated precipitation in the northwestern flank.The role of the WTP was verified by regression analyses on the interannual variation of the WTP sea surface temperature anomaly(SSTA).On the other hand,the WTP has undergone prominent warming during the past few decades,resulting from decadal to long-term changes and favoring extreme warm conditions.Through a mechanism similar to the interannual variation,the decadal to long-term changes have reinforced the influence of WTP warming on the temperature over CSC,contributing to the more frequent hot midsummers recently.It is estimated that more than 50%of the temperature anomaly over CSC in the 2017 midsummer was due to the WTP warming,and 40%was related to the decadal to long-term changes of the WTP SSTA. 展开更多
关键词 HOT MIDSUMMER CENTRAL and South China western tropical Pacific DECADAL to long-term changes
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INTELLIGENT ALGORITHMS FOR SOLVING CNOP AND THEIR APPLICATIONS IN ENSO PREDICTABILITY AND TROPICAL CYCLONE ADAPTIVE OBSERVATIONS
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作者 穆斌 张琳琳 +4 位作者 袁时金 钱一闻 温仕成 颜景豪 周菲凡 《热带气象学报:英文版》 SCIE 2019年第1期63-81,共19页
Some intelligent algorithms(IAs)proposed by us,including swarm IAs and single individual IAs,have been applied to the Zebiak-Cane(ZC)model to solve conditional nonlinear optimal perturbation(CNOP)for studying El Ni?o-... Some intelligent algorithms(IAs)proposed by us,including swarm IAs and single individual IAs,have been applied to the Zebiak-Cane(ZC)model to solve conditional nonlinear optimal perturbation(CNOP)for studying El Ni?o-Southern Oscillation(ENSO)predictability.Compared to the adjoint-based method(the ADJ-method),which is referred to as a benchmark,these IAs can achieve approximate CNOP results in terms of magnitudes and patterns.Using IAs to solve CNOP can avoid the use of an adjoint model and widen the application of CNOP in numerical climate and weather modeling.Of the proposed swarm IAs,PCA-based particle swarm optimization(PPSO)obtains CNOPs with the best patterns and the best stability.Of the proposed single individual IAs,continuous tabu search algorithm with sine maps and staged strategy(CTS-SS)has the highest efficiency.In this paper,we compare the validity,stability and efficiency of parallel PPSO and CTS-SS using these two IAs to solve CNOP in the ZC model for studying ENSO predictability.The experimental results show that CTS-SS outperforms parallel PPSO except with respect to stability.At the same time,we are also concerned with whether these two IAs can effectively solve CNOP when applied to more complicated models.Taking the sensitive areas identification of tropical cyclone adaptive observations as an example and using the fifth-generation mesoscale model(MM5),we design some experiments.The experimental results demonstrate that each of these two IAs can effectively solve CNOP and that parallel PPSO has a higher efficiency than CTS-SS.We also provide some suggestions on how to choose a suitable IA to solve CNOP for different models. 展开更多
关键词 CNOP single individual INTELLIGENT ALGORITHMS swarm INTELLIGENT ALGORITHMS ENSO PREDICTABILITY tropical cyclone adaptive observations
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