SPIE Asia-Pacific Remote Sensing最新文献_第8页

The spatio-temporal structures and role of low- and high-frequency intraseasonal modes in Indian Summer monsoon rainfall observed in TRMM data TRMM资料观测的低、高频季内模态在印度夏季风降水中的时空结构及其作用

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2228030

N. Karmakar, A. Chakraborty, R. Nanjundiah

{"title":"The spatio-temporal structures and role of low- and high-frequency intraseasonal modes in Indian Summer monsoon rainfall observed in TRMM data","authors":"N. Karmakar, A. Chakraborty, R. Nanjundiah","doi":"10.1117/12.2228030","DOIUrl":"https://doi.org/10.1117/12.2228030","url":null,"abstract":"This study uses precipitation estimates from the Tropical Rainfall Measuring Mission to estimate the intensity and examine the spatiotemporal patterns in the modes found in intraseasonal timescale over the Indian monsoon region during boreal summer. Here, using multichannel singular spectrum analysis, two dominant modes of oscillations are found in the intraseasonal timescale with periodicity of 10–20-days and 20–60-days, respectively. 20–60-days mode shows northward propagation from the equatorial Indian Ocean linked with the eastward propagating modes of convective systems over the tropics. 10–20-days mode shows very complex structure with a northwestward propagating anomaly pattern emanating from the Indonesian coast moving towards central India. This pattern is found to have a possible interaction with a structure emerging from higher latitudes propagating southeastwards. The two intraseasonal modes contribute comparable amount to the total rainfall variability. The intensity of the 20–60-days (10–20-days) mode show significantly strong inverse (direct) relationship with all- India June–September rainfall and both the modes exhibit profound variability in their intensity in interannual scale. This study also establishes that the probability of getting good amount of rainfall (no rainfall) over central India increases significantly if the two intraseasonal modes exhibit positive (negative) anomalies over the region. Relation between the ISO intensities and sea surface temperature is also discussed. This study points towards the fact that the knowledge of ISO phases can increase the skill in the probabilistic forecasting of rainfall over India.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128402129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Impact of Megha-Tropiques SAPHIR radiance assimilation on the simulation of tropical cyclones over Bay of Bengal 大热带SAPHIR辐射同化对孟加拉湾热带气旋模拟的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223305

D. M, D. Gopalakrishnan, A. Chandrasekar, S. K. Singh, V. S. Prasad

{"title":"Impact of Megha-Tropiques SAPHIR radiance assimilation on the simulation of tropical cyclones over Bay of Bengal","authors":"D. M, D. Gopalakrishnan, A. Chandrasekar, S. K. Singh, V. S. Prasad","doi":"10.1117/12.2223305","DOIUrl":"https://doi.org/10.1117/12.2223305","url":null,"abstract":"Impact of SAPHIR radiance assimilation on the simulation of tropical cyclones over Indian region has been investigated using the Weather Research and Forecasting (WRF) model. Three cyclones that formed over Bay of Bengal have been considered in the present study. Assimilation methodology used here is the three dimensional variational (3DVar) scheme within the WRF model. With the initial and boundary conditions from Global Forecasting System (GFS) analyses from the National Centres for Environmental Prediction (NCEP), a control run (CTRL) without assimilation of any data and a 3DVar run with the assimilation of SAPHIR radiance have been performed. Both model simulations have been compared with the observations from India Meteorological Department (IMD), Tropical Rainfall Measurement Mission (TRMM), and analysis fields from GFS. Detailed analysis reveals that, the SAPHIR radiance assimilation has led to significant improvement in the simulation of all the three cyclones in terms of cyclone track, intensity, accumulated rainfall. The simulation of warm core structure and relative vorticity profile of each cyclone by 3DVar run are found to be more closer to GFS analyses, when compared with the CTRL run.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127112753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of GNSS-IPW observations on NGFS GNSS-IPW观测对NGFS的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2222748

C. Johny, V. S. Prasad

{"title":"Impact of GNSS-IPW observations on NGFS","authors":"C. Johny, V. S. Prasad","doi":"10.1117/12.2222748","DOIUrl":"https://doi.org/10.1117/12.2222748","url":null,"abstract":"The accurate estimation of water vapour with high spatial and temporal resolution is needed for operational weather forecasts and weather and climate research. Moisture representation in numerical weather prediction models is inadequate for forecasting meso-scale precipitation events and accurate information of middle and upper tropospheric moisture determines strength, effectiveness and longevity deep convective processes. Global Navigation Satellite System (GNSS) provides a way for measuring atmospheric humidity continuously at a low operational cost by co-locating GPS receiver with meteorological sensor. Impact of assimilation of GPS-IPW observations from NOAA-NWS and EUMETNET network on NCMRWF GFS forecast is investigated during May-June period in 2014. Impact of assimilation of GPS-IPW observations are not only confined to the regions of dense GPS-IPW network, but can be seen in other regions also. Ingestion of IPW observations impacted prediction of rainfall over the Indian monsoon region even though very few IPW stations located in the region. Impact of assimilation is not uniform on temperature, wind and humidity and different over different region. GPS-IPW observations can impact forecast of individual rainfall events at large and major impact on rainfall forecast is seen in the regions of large integrated precipitable water in the model. In India MoES has already setup many GPS-IPW stations and also some more are in the pipeline . The quality of these present observations from MoES and plans for the future GPS-IPW stations are discussed.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"332 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123313951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Recent land use/land cover changes and their impact on the evolution and structure of thunderstorm in New Delhi 新德里近期土地利用/土地覆盖变化及其对雷暴演变和结构的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223602

Ashu Mamgain, Unnikrishnan C. K., E. Rajagopal

引用次数: 2

Prediction of tropical cyclone over North Indian Ocean using WRF model: sensitivity to scatterometer winds, ATOVS and ATMS radiances 使用WRF模式预测北印度洋热带气旋:对散射计风、ATOVS和ATMS辐射的敏感性

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223615

V. Dodla, D. Srinivas, H. Dasari, Chinna Satyanarayana Gubbala

{"title":"Prediction of tropical cyclone over North Indian Ocean using WRF model: sensitivity to scatterometer winds, ATOVS and ATMS radiances","authors":"V. Dodla, D. Srinivas, H. Dasari, Chinna Satyanarayana Gubbala","doi":"10.1117/12.2223615","DOIUrl":"https://doi.org/10.1117/12.2223615","url":null,"abstract":"Tropical cyclone prediction, in terms of intensification and movement, is important for disaster management and mitigation. Hitherto, research studies were focused on this issue that lead to improvement in numerical models, initial data with data assimilation, physical parameterizations and application of ensemble prediction. Weather Research and Forecasting (WRF) model is the state-of-art model for cyclone prediction. In the present study, prediction of tropical cyclone (Phailin, 2013) that formed in the North Indian Ocean (NIO) with and without data assimilation using WRF model has been made to assess impacts of data assimilation. WRF model was designed to have nested two domains of 15 and 5 km resolutions. In the present study, numerical experiments are made without and with the assimilation of scatterometer winds, and radiances from ATOVS and ATMS. The model performance was assessed in respect to the movement and intensification of cyclone. ATOVS data assimilation experiment had produced the best prediction with least errors less than 100 km up to 60 hours and producing pre-deepening and deepening periods accurately. The Control and SCAT wind assimilation experiments have shown good track but the errors were 150-200 km and gradual deepening from the beginning itself instead of sudden deepening.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"225 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116134519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Genesis of elevated aerosol loading over the Indian region 印度地区气溶胶负荷升高的成因

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223480

S. S. Prijith, P. V. N. Rao, M. Mohan

{"title":"Genesis of elevated aerosol loading over the Indian region","authors":"S. S. Prijith, P. V. N. Rao, M. Mohan","doi":"10.1117/12.2223480","DOIUrl":"https://doi.org/10.1117/12.2223480","url":null,"abstract":"Elevated aerosols assume importance as the diabatic heating due to aerosol absorption is more intense at higher altitudes where the atmosphere becomes thinner. Indian region, especially its central and northern latitudes, experiences significant loading of elevated aerosols during pre-monsoon and summer months. Genesis of elevated aerosol loading over Indian region is investigated in the present study, using multi-year satellite observations from Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and Moderate Resolution Imaging Spectroradiometer (MODIS) along with reanalysis winds from MERRA. Central India is observed to have prominent aerosols loading at higher altitudes during pre-monsoon season, whereas it is during summer months over north-west India. Further analysis reveals that the elevated aerosols over Indian region in pre-monsoon and summer months are significantly contributed by transported mineral dust from the arid continental regions at west. In addition to the mineral dust advection, aerosols at higher altitudes over Indian region are enriched by strong convection and associated vertical transport of surface level aerosols. Vertical transport of aerosols observed over Indian region during pre-monsoon and summer months is aided by intense convergence at the surface level and divergence at the upper level. Moreover, aerosol source/sink strength estimated using aerosol flux continuity equation show significant aerosol production over central India during pre-monsoon. Strong vertical transport prevails during pre-monsoon uplifts the locally produced aerosols, with considerable anthropogenic fraction, to higher altitudes where their impacts would be more intense.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123877711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Analysis and evaluation of Observing System Simulation Experiments (OSSEs) forecast data for Indian summer monsoon 印度夏季风观测系统模拟试验(OSSEs)预报资料分析与评价

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223656

M. Deshpande, P. Mukhopadhyay, M. Masutani, Zaizhong Ma, L. Riishojgaard, M. Hardesty, D. Emmitt, T. N. Krishnamurti, B. Goswami

{"title":"Analysis and evaluation of Observing System Simulation Experiments (OSSEs) forecast data for Indian summer monsoon","authors":"M. Deshpande, P. Mukhopadhyay, M. Masutani, Zaizhong Ma, L. Riishojgaard, M. Hardesty, D. Emmitt, T. N. Krishnamurti, B. Goswami","doi":"10.1117/12.2223656","DOIUrl":"https://doi.org/10.1117/12.2223656","url":null,"abstract":"An attempt is made here to evaluate the skill of forecast during boreal summer monsoon regime over the Indian region using the Observation Simulation System Experiment (OSSE) with Doppler Wind LIDAR (DWL) onboard International Space Station (ISS), assimilated in the initial condition. Through various techniques such as pattern correlation, root mean square error etc, we found that there is some positive impact of assimilating the DWL data on the forecast particularly at the lower tropospheric level. Impact on lowering the RMSE is seen for wind fields in the 850 and 500 hPa over Indian domain but not much impact is seen over larger domain. The moisture field and cloud also show marginal impact due to assimilation of DWL. This indicates that possibly due to lower spatial resolution of DWL data and more data gap over Indian and surrounding oceanic region, the impact on forecast is less. However, it shows the promise that monsoon being a convectively coupled system; increase in spatial data by DWL may better resolve the low level wind and subsequently the low level shear which is important for convection trigger in boundary layer.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130646362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Aerosols-cloud interaction during active-break cycle of Indian summer monsoon from satellite observations and cloud resolving model simulations 来自卫星观测和云解析模式模拟的印度夏季风主动中断周期中的气溶胶-云相互作用

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2228032

A. Bhattacharya, V. Venugopal, A. Chakraborty

引用次数: 0

Efforts in assimilating Indian satellite data in the NGFS and monitoring of their quality 将印度卫星数据纳入NGFS并监测其质量的努力

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2223550

V. S. Prasad, S. K. Singh

{"title":"Efforts in assimilating Indian satellite data in the NGFS and monitoring of their quality","authors":"V. S. Prasad, S. K. Singh","doi":"10.1117/12.2223550","DOIUrl":"https://doi.org/10.1117/12.2223550","url":null,"abstract":"Megha-Tropiques (MT) is an Indo-French Joint Satellite Mission, launched on 12 October 2011. MT-SAPHIR is a sounding instrument with 6 channels near the absorption band of water vapor at 183 GHz, for studying the water cycle and energy exchanges in the tropics. The main objective of this mission is to understand the life cycle of convective systems that influence the tropical weather and climate and their role in associated energy and moisture budget of the atmosphere in tropical regions. India also has a prestigious space programme and has launched the INSAT-3D satellite on 26 July 2013 which has an atmospheric sounder for the first time along with improved VHRR imager. NCMRWF (National Centre for Medium Range Weather Forecasting) is regularly receiving these new datasets and also making changes to its Global Data Assimilation Forecasting (GDAF) system from time-to-time to assimilate these new datasets. A well planned strategy involving various steps such as monitoring of data quality, development of observation operator and quality control procedures, and finally then studying its impact on forecasts is developed to include new observations in global data analysis system. By employing this strategy observations having positive impact on forecast quality such as MT-SAPHIR, and INSAT-3D Clear Sky Radiance (CSR) products are identified and being assimilated in the Global Data Assimilation and Forecasting (GDAF) system.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"26 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113958156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Quantifying and monitoring convection intensity from mm-wave sounder observations 从毫米波测深观测中量化和监测对流强度

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-03 DOI: 10.1117/12.2228186

Z. Haddad, Randy S. Sawaya, S. Kacimi, O. Sy, J. Steward

{"title":"Quantifying and monitoring convection intensity from mm-wave sounder observations","authors":"Z. Haddad, Randy S. Sawaya, S. Kacimi, O. Sy, J. Steward","doi":"10.1117/12.2228186","DOIUrl":"https://doi.org/10.1117/12.2228186","url":null,"abstract":"Few systematic attempts to interpret the measurements of mm-wave radiometers over clouds and precipitation have been made to date because the scattering signatures of hydrometeors at these frequencies are very difficult to model. The few algorithms that have been developed try to retrieve surface precipitation, to which the observations are partially correlated but not directly sensitive. In fact, over deep clouds, mm-wave radiometers are most sensitive to the scattering from solid hydrometeors within the upper levels of the cloud. In addition, mm-wave radiometers have a definite advantage over the lower-frequency window-channel radiometers in that they have finer resolution and can therefore explicitly resolve deep convection. Preliminary analyses (in particular of NOAA's MHS brightness temperatures, as well as Megha-Tropiques's SAPHIR observations) indicate that the measurements are indeed very sensitive to the depth and intensity of convection. The challenge is to derive a robust approach to make quantitative estimates of the convection, for example the height and depth of the condensed water, directly from the mm-wave observations, as a function of horizontal location. To avoid having to rely on a specific set of microphysical assumptions, this analysis exploits the substantial amount of nearly- simultaneous coincident observations by mm-wave radiometers and orbiting atmospheric profiling radars in order to enforce unbiased consistency between the calculated brightness temperatures and the radar and radiometer observations.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126396029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0