Ocean colour remote sensing is one of the conventional methods in satellite oceanography used to study the biological response of the upper ocean to the tropical cyclones. This paper aims to study the impact of the Ve...Ocean colour remote sensing is one of the conventional methods in satellite oceanography used to study the biological response of the upper ocean to the tropical cyclones. This paper aims to study the impact of the Very Severe Cyclonic storm PHAILIN, and its consequence on the surface chlorophyll-aconcentration distribution in the Bay of Bengal using Oceansat-2 Ocean Colour Monitor (OCM). The impact of this cyclone on ocean primary productivity has been studied using MODIS-A data. Sea surface temperature (SST) plays an important role in the generation of primary productivity along with the other oceanographic parameters;SST patterns in the Bay of Bengal during the cyclone period were studied. From the analysis, it is observed that the chlorophyll-aconcentration has increased from 1.08 (before) to 7.06 mg/m3 after the cyclone with an SST drop of ~3°C (29.19°C to 26°C). The primary productivity has increased from 410.0506 to 779.9814 mg/C/m2/day after the cyclone. In addition to the above analysis, an attempt has also been made to study the impact of cyclone intensity on the chlorophyll concentration. The study shows that the comparison between cyclone intensity (CI) and chlorophyll concentration shows a positive relationship.展开更多
Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of t...Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of turbulent heat flux(THF).By combining multiple buoy observations along the south north storm track,we investigated the THF anomalies associated with tropical storm Danas(2019)in the East China Sea(ECS)during its complete life cycle from the intensification stage to the mature stage and finally to its dissipation on land.The storm passage is characterized by strong winds of 10-20 m/s and a sea level pressure below 1000 hPa,resulting in a substantial enhancement of THF.Latent heat(LH)fluxes are most strongly affected by wind speed,with a gradually increasing contribution of humidity along the trajectory.The relative contributions of wind speed and temperature anomalies to sensible heat(SH)depend on the stability of the boundary layer.Under stable conditions,SH variations are driven by wind speed,while under near-neutral conditions,SH variations are driven by temperature.A comparison of the observed THF and associated variables with outputs from the ERA 5 and MERRA 2 reanalysis products reveals that the reanalysis products can reproduce the basic evolution and composition of the observed THF.However,under extreme weather conditions,temperature and humidity variations are poorly captured by ERA 5 and MERRA 2,leading to large LH and SH errors.The differences in the observed and reproduced LH and SH during the passage of Danas amount to 26.1 and 6.6 W/m^(2) for ERA 5,respectively,and to 39.4 and 12.5 W/m^(2) for MERRA 2,respectively.These results demonstrate the need to improve the representation of tropical cyclones in reanalysis products to better predict their intensification process and reduce their damage.展开更多
Southern Malawi is continuously affected by tropical cyclone-related floods(TCRFs),which have negative consequences on households'livelihoods,thereby displacing most households to neighbouring communities of Mozam...Southern Malawi is continuously affected by tropical cyclone-related floods(TCRFs),which have negative consequences on households'livelihoods,thereby displacing most households to neighbouring communities of Mozambique.The TCRFs have further threatened national,regional,community,and household food security agenda,which is already constrained by poverty,poor agricultural practices,low use of improved varieties,unaffordable inorganic fertilizers,and fragmenting landholding sizes.Accordingly,households have indigenously engineered resilience-based Sustainable Landscape Management(SLM)practices,like intercropping,agroforestry,cover cropping,and soil and water conservation practices,against the adverse effects of TCRFs on-farm productivity.Hence,this study examines the effect of TCRFs and SLM adoption on-farm productivity.While using rigorous endogenous switching regression econometric tools,the study finds TCRFs reducing farm productivity by 27 percent.After SLM adoption,the study observes farm productivity enhancement by 29-126 percent when households adopt at least one SLM practices under varying degrees of TCRFs.Despite the highlighted advantages of SLM adoption,female farmers are less likely to adopt SLM practices because they do not have access to productive resources.Hence,the study proposes the need of gender targeted extension services,accompanied by some seed capital for SLM adoption.Besides,there is need to sensitize farmers on the complementarities between inorganic fertilizer and SLM practices.Lastly,future studies should assess the effect of sustained SLM adoption or dis-adoption and input intensification on farm productivity.展开更多
文摘Ocean colour remote sensing is one of the conventional methods in satellite oceanography used to study the biological response of the upper ocean to the tropical cyclones. This paper aims to study the impact of the Very Severe Cyclonic storm PHAILIN, and its consequence on the surface chlorophyll-aconcentration distribution in the Bay of Bengal using Oceansat-2 Ocean Colour Monitor (OCM). The impact of this cyclone on ocean primary productivity has been studied using MODIS-A data. Sea surface temperature (SST) plays an important role in the generation of primary productivity along with the other oceanographic parameters;SST patterns in the Bay of Bengal during the cyclone period were studied. From the analysis, it is observed that the chlorophyll-aconcentration has increased from 1.08 (before) to 7.06 mg/m3 after the cyclone with an SST drop of ~3°C (29.19°C to 26°C). The primary productivity has increased from 410.0506 to 779.9814 mg/C/m2/day after the cyclone. In addition to the above analysis, an attempt has also been made to study the impact of cyclone intensity on the chlorophyll concentration. The study shows that the comparison between cyclone intensity (CI) and chlorophyll concentration shows a positive relationship.
基金Supported by the National Natural Science Foundation of China(Nos.42122040,42076016)。
文摘Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of turbulent heat flux(THF).By combining multiple buoy observations along the south north storm track,we investigated the THF anomalies associated with tropical storm Danas(2019)in the East China Sea(ECS)during its complete life cycle from the intensification stage to the mature stage and finally to its dissipation on land.The storm passage is characterized by strong winds of 10-20 m/s and a sea level pressure below 1000 hPa,resulting in a substantial enhancement of THF.Latent heat(LH)fluxes are most strongly affected by wind speed,with a gradually increasing contribution of humidity along the trajectory.The relative contributions of wind speed and temperature anomalies to sensible heat(SH)depend on the stability of the boundary layer.Under stable conditions,SH variations are driven by wind speed,while under near-neutral conditions,SH variations are driven by temperature.A comparison of the observed THF and associated variables with outputs from the ERA 5 and MERRA 2 reanalysis products reveals that the reanalysis products can reproduce the basic evolution and composition of the observed THF.However,under extreme weather conditions,temperature and humidity variations are poorly captured by ERA 5 and MERRA 2,leading to large LH and SH errors.The differences in the observed and reproduced LH and SH during the passage of Danas amount to 26.1 and 6.6 W/m^(2) for ERA 5,respectively,and to 39.4 and 12.5 W/m^(2) for MERRA 2,respectively.These results demonstrate the need to improve the representation of tropical cyclones in reanalysis products to better predict their intensification process and reduce their damage.
文摘Southern Malawi is continuously affected by tropical cyclone-related floods(TCRFs),which have negative consequences on households'livelihoods,thereby displacing most households to neighbouring communities of Mozambique.The TCRFs have further threatened national,regional,community,and household food security agenda,which is already constrained by poverty,poor agricultural practices,low use of improved varieties,unaffordable inorganic fertilizers,and fragmenting landholding sizes.Accordingly,households have indigenously engineered resilience-based Sustainable Landscape Management(SLM)practices,like intercropping,agroforestry,cover cropping,and soil and water conservation practices,against the adverse effects of TCRFs on-farm productivity.Hence,this study examines the effect of TCRFs and SLM adoption on-farm productivity.While using rigorous endogenous switching regression econometric tools,the study finds TCRFs reducing farm productivity by 27 percent.After SLM adoption,the study observes farm productivity enhancement by 29-126 percent when households adopt at least one SLM practices under varying degrees of TCRFs.Despite the highlighted advantages of SLM adoption,female farmers are less likely to adopt SLM practices because they do not have access to productive resources.Hence,the study proposes the need of gender targeted extension services,accompanied by some seed capital for SLM adoption.Besides,there is need to sensitize farmers on the complementarities between inorganic fertilizer and SLM practices.Lastly,future studies should assess the effect of sustained SLM adoption or dis-adoption and input intensification on farm productivity.
