SPIE Asia-Pacific Remote Sensing最新文献_第3页

Wind from Indian Doppler Weather Radars: a data assimilation view point 来自印度多普勒天气雷达的风:数据同化的观点

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-09 DOI: 10.1117/12.2223691

Devajyoti Dutta, S. Mallick, K. Jyothi, J. George, D. Kumar

引用次数: 0

Dust forecast over North Africa: verification with satellite and ground based observations 北非沙尘预报:卫星和地面观测的验证

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-09 DOI: 10.1117/12.2223596

Aditi Singh, Sumit Kumar, J. George

{"title":"Dust forecast over North Africa: verification with satellite and ground based observations","authors":"Aditi Singh, Sumit Kumar, J. George","doi":"10.1117/12.2223596","DOIUrl":"https://doi.org/10.1117/12.2223596","url":null,"abstract":"Arid regions of North Africa are considered as one of the major dust source. Present study focuses on the forecast of aerosol optical depth (AOD) of dust over different regions of North Africa. NCMRWF Unified Model (NCUM) produces dust AOD forecasts at different wavelengths with lead time upto 240 hr, based on 00UTC initial conditions. Model forecast of dust AOD at 550 nm up to 72 hr forecast, based on different initial conditions are verified against satellite and ground based observations of total AOD during May–June 2014 with the assumption that except dust, presence of all other aerosols type are negligible. Location specific and geographical distribution of dust AOD forecast is verified against Aerosol Robotic Network (AERONET) station observations of total and coarse mode AOD. Moderate Resolution Imaging Spectroradiometer (MODIS) dark target and deep blue merged level 3 total aerosol optical depth (AOD) at 550 nm and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) retrieved dust AOD at 532 nm are also used for verification. CALIOP dust AOD was obtained by vertical integration of aerosol extinction coefficient at 532 nm from the aerosol profile level 2 products. It is found that at all the selected AERONET stations, the trend in dust AODs is well predicted by NCUM up to three days advance. Good correlation, with consistently low bias (~ ±0.06) and RMSE (~ 0.2) values, is found between model forecasts and point measurements of AERONET, except over one location Cinzana (Mali). Model forecast consistently overestimated the dust AOD compared to CALIOP dust AOD, with a bias of 0.25 and RMSE of 0.40.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114423228","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

Precipitation and cloud microstructure variations between two southern Indian stations 两个南印度站降水和云微观结构的变化

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-09 DOI: 10.1117/12.2218458

Balaji Kumar Seela, K. Reddy, J. Jayalakshmi, T. N. Rao, P. Lin, Chian‐Yi Liu, U. Kumar

引用次数: 3

Impact of El Nino and La Nina on the meteorological elements 厄尔尼诺和拉尼娜对气象要素的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2236250

R. Jaiswal, S. T., Samuthra G., P. M., V. R

引用次数: 2

Comparison of INSAT-3D AOD over Indian region with satellite- and ground-based measurements: a data assimilation perspective 印度地区INSAT-3D AOD与卫星和地面测量数据的比较:数据同化视角

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2223527

Sumit Kumar, J. George, M. N. R. Sreevathsa, S. Indira Rani

{"title":"Comparison of INSAT-3D AOD over Indian region with satellite- and ground-based measurements: a data assimilation perspective","authors":"Sumit Kumar, J. George, M. N. R. Sreevathsa, S. Indira Rani","doi":"10.1117/12.2223527","DOIUrl":"https://doi.org/10.1117/12.2223527","url":null,"abstract":"This paper aims at comparing the INSAT-3D AOD with other space based observations over the continental regions. INSAT-3D launched in 2013 is an advanced geostationary weather satellite of India at 82° East longitude provides Aerosol Optical Depth (AOD) observations at 650 nm over both land and ocean. The level-3 daily AOD measurements from MODIS (both Aqua and Terra) and MISR are used for comparison with that from INSAT-3D. This work is applied during premonsoon season of 2015. Overall statistical scores and systematic errors are compared to characterize various error sources. Our study indicates that significant differences exist between different aerosol observations which may be partly due to retrieval algorithm, sensor configurations and temporal sampling. Comparison of INSAT observed AOD shows less bias towards MISR and MODIS-Terra observed AOD than with MODIS-Aqua. The INSAT observations over oceanic region have better correlation, minimum bias and rmse than land region. Overall, the mean bias of the dataset is ±0.05, with a root mean square error of 0.22, but these errors are also found highly dependent on geographical region. Additionally, we compared INSAT 660 nm AOD with two AERONET ground stations. The comparison of INSAT with different observations shows that the retrieved AOD is closer to the ground-based data than the MISR and MODIS AOD.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"9876 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129442887","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: 3

Variability of aerosol optical depth and aerosol radiative forcing over Northwest Himalayan region 西北喜马拉雅地区气溶胶光学深度和气溶胶辐射强迫的变率

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2223641

Shaik Darga Saheb, Y. Kant, D. Mitra

{"title":"Variability of aerosol optical depth and aerosol radiative forcing over Northwest Himalayan region","authors":"Shaik Darga Saheb, Y. Kant, D. Mitra","doi":"10.1117/12.2223641","DOIUrl":"https://doi.org/10.1117/12.2223641","url":null,"abstract":"In recent years, the aerosol loading in India is increasing that has significant impact on the weather/climatic conditions. The present study discusses the analysis of temporal (monthly and seasonal) variation of aerosol optical depth(AOD) by the ground based observations from sun photometer and estimate the aerosol radiative forcing and heating rate over selected station Dehradun in North western Himalayas, India during 2015. The in-situ measurements data illustrate that the maximum seasonal average AOD observed during summer season AOD at 500nm ≈ 0.59±0.27 with an average angstrom exponent, α ≈0.86 while minimum during winter season AOD at 500nm ≈ 0.33±0.10 with angstrom exponent, α ≈1.18. The MODIS and MISR derived AOD was also compared with the ground measured values and are good to be in good agreement. Analysis of air mass back trajectories using HYSPLIT model reveal that the transportation of desert dust during summer months. The Optical Properties of Aerosols and clouds (OPAC) model was used to compute the aerosol optical properties like single scattering albedo (SSA), Angstrom coefficient (α) and Asymmetry(g) parameter for each day of measurement and they are incorporated in a Discrete Ordinate Radiative Transfer model, i.e Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) to estimate the direct short-wave (0.25 to 4 μm) Aerosol Radiative forcing at the Surface (SUR), the top-of-atmosphere (TOA) and Atmosphere (ATM). The maximum Aerosol Radiative Forcing (ARF) was observed during summer months at SUR ≈ -56.42 w/m2, at TOA ≈-21.62 w/m2 whereas in ATM ≈+34.79 w/m2 with corresponding to heating rate 1.24°C/day with in lower atmosphere.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114975822","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

A merged aerosol dataset based on MODIS and MISR Aerosol Optical Depth products 基于MODIS和MISR气溶胶光学深度产品的合并气溶胶数据集

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2223485

Manoj K. Singh, R. Gautam, P. Venkatachalam

{"title":"A merged aerosol dataset based on MODIS and MISR Aerosol Optical Depth products","authors":"Manoj K. Singh, R. Gautam, P. Venkatachalam","doi":"10.1117/12.2223485","DOIUrl":"https://doi.org/10.1117/12.2223485","url":null,"abstract":"Aerosol Optical Depth (AOD) products available from MODIS and MISR observations are widely used for aerosol characterization, and global/environmental change studies. These products are based on different retrieval-algorithms, resolutions, sampling, and cloud-screening schemes, which have led to global/regional biases. Thus a merged product is desirable which bridges this gap by utilizing strengths from each of the sensors. In view of this, we have developed a “merged” AOD product based on MODIS and MISR AOD datasets, using Bayesian principles which takes error distributions from ground-based AOD measurements (from AERONET). Our methodology and resulting dataset are especially relevant in the scenario of combining multi-sensor retrievals for satellite-based climate data records; particularly for long-term studies involving AOD. Specifically for MISR AOD product, we also developed a methodology to produce a gap-filled dataset, using geostatistical methods (e.g. Kriging), taking advantage of available MODIS data. Merged and spatially-complete AOD datasets are inter-compared with other satellite products and with AERONET data at three stations- Kanpur, Jaipur and Gandhi College, in the Indo-Gangetic Plains. The RMSE of merged AOD (0.08-0.09) is lower than MISR (0.11-0.20) and MODIS (0.15-0.27). It is found that merged AOD has higher correlation with AERONET data (r within 0.92-0.95), compared to MISR (0.74-0.86) and MODIS (0.69-0.84) data. In terms of Expected Error, the accuracy of valid merged AOD is found to be superior as percent of merged AOD within error envelope are larger (71-92%), compared to MISR (43-61%) and MODIS (50-70%).","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130615713","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: 5

Long-term trend in tropospheric carbon monoxide over the globe 全球对流层一氧化碳的长期趋势

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2223380

I. Girach, P. Nair

{"title":"Long-term trend in tropospheric carbon monoxide over the globe","authors":"I. Girach, P. Nair","doi":"10.1117/12.2223380","DOIUrl":"https://doi.org/10.1117/12.2223380","url":null,"abstract":"Tropospheric carbon monoxide (CO) is an air pollutant and indirect greenhouse gas which plays a major role in atmospheric chemistry involving hydroxyl (OH) radical. We utilised the remote-sensing retrievals of lower-tropospheric CO (at 900 hPa) from Measurements of Pollution in the Troposphere (MOPITT) aboard Terra-satellite for the period of ~15 years. Using simple linear regression model, we estimated the decreasing trend of ~0-2 %year-1 in the lowertropospheric CO over the globe. Utilising the in-situ measurements of surface-CO over 83 locations carried out by the NOAA (National Oceanic and Atmospheric Administration) network, we confirmed the observed negative trend as surface-CO showed decreasing trend over most of the locations. To estimate the trend in columnar CO, we utilised multiple retrievals of from different satellites, MOPITT, AIRS (Atmospheric InfraRed Sounder), and TES (Tropospheric Emission Spectrometer). All data sets show the decreasing trend of 0.2-0.5 %year-1 in columnar CO when averaged over entire globe. However, the heterogeneity in the trend is observed on regional basis. The retrievals of upper-tropospheric CO (at 200 hPa) from MOPITT and AIRS show an increasing trend of 1-4 %year-1 over the globe. However, the retrievals of upper-tropospheric CO from MLS (Microwave Limb Sounder) show decreasing trend. Further investigations are needed to confirm the trend in the upper-tropospheric CO over the globe. The decreasing trend in lower-tropospheric CO and columnar CO could be due to moistening of troposphere and/or increase in tropospheric ozone, causing increase in OH radical (strengthening the depletion of lower-tropospheric CO).","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127839108","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

Effects of South Asian dust storm on air quality over the capital city of India 南亚沙尘暴对印度首都空气质量的影响

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-06 DOI: 10.1117/12.2223548

Y. Yarragunta, S. Srivastava

{"title":"Effects of South Asian dust storm on air quality over the capital city of India","authors":"Y. Yarragunta, S. Srivastava","doi":"10.1117/12.2223548","DOIUrl":"https://doi.org/10.1117/12.2223548","url":null,"abstract":"In the present study, an intense unseasonal dust storm has been analyzed during third week of March 2012 from multi satellite datasets and from surface measurements over National Capital Region (NCR), Delhi. The intrusion of dust over study region has increased the MODIS Aerosol Optical Depth at 550 nm more than 1.0 whereas significant decrease in Angstrom Exponent (α) has been observed . Very high UV aerosol Index (> 2) over study location indicates the presence of UV absorbing aerosols . Fire activities are found to be negligible over the source region confirming the effect of dust storm. Strong southwesterly winds prevailed over northern Arabian Sea which trans ported the dust plume across the oceanic region towards Indian capital region. In-situ measurements of PM 2.5 and PM10, obtained from CPCB observational site over the IGI airport, NCR Delhi, showed abrupt increase on 20, 21 March. Eight hourly average concentration of the particulate matters less than 10 μm (PM10) is found to be ~990 μg/m3 and particulate matters less than 2.5 μm (PM2.5) is found to be ~900 μg/m3 over IGI Airport, NCR Delhi. These values are remarkably higher as compared to the daily National Ambient Air Quality Standards (NAAQS) i.e. 100 μg/m3 and 60 μg/m3 for PM10 and PM2.5 respectively. In addition, Vertical distribution of dust has been examined using CALIPSO observation. The layer of dust is found to be trapped within lower 3 km in altitude. The Potential Source Contribution Function (PSCF) modeling has been carried out to identify the specific source locations.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130527916","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: 3

Heavy rains over Chennai and surrounding areas as captured by Doppler weather radar during Northeast Monsoon 2015: a case study 2015年东北季风期间多普勒天气雷达捕捉到的金奈及周边地区的暴雨:一个案例研究

SPIE Asia-Pacific Remote Sensing Pub Date : 2016-05-05 DOI: 10.1117/12.2239563

Ray Kamaljit, B. Kannan, S. Stella, Bikram Sen, Pradip Sharma, S. Thampi

{"title":"Heavy rains over Chennai and surrounding areas as captured by Doppler weather radar during Northeast Monsoon 2015: a case study","authors":"Ray Kamaljit, B. Kannan, S. Stella, Bikram Sen, Pradip Sharma, S. Thampi","doi":"10.1117/12.2239563","DOIUrl":"https://doi.org/10.1117/12.2239563","url":null,"abstract":"During the Northeast monsoon season, India receives about 11% of its annual rainfall. Many districts in South Peninsula receive 30-60% of their annual rainfall. Coastal Tamil Nadu receives 60% of its annual rainfall and interior districts about 40-50 %. During the month of November, 2015, three synoptic scale weather systems affected Tamil Nadu and Pondicherry causing extensive rainfall activity over the region. Extremely heavy rains occurred over districts of Chennai, Thiruvallur and Kancheepuram, due to which these 3 districts were fully inundated. 122 people in Tamil Nadu were reported to have died due to the flooding, while over 70,000 people had been rescued. State government reported flood damage of the order of around Rs 8481 Crores. The rainfall received in Chennai district during 1.11.2015 to 5.12.2015 was 1416.8 mm against the normal of 408.4 mm. The extremely heavy rains were found to be associated with strong wind surges at lower tropospheric levels, which brought in lot of moisture flux over Chennai and adjoining area. The subtropical westerly trough at mid-tropospheric levels extended much southwards than its normal latitude, producing favorable environment for sustained rising motions ahead of approaching trough over coastal Tamil Nadu. Generated strong upward velocities in the clouds lifted the cloud tops to very high levels forming deep convective clouds. These clouds provided very heavy rainfall of the order of 150-200 mm/hour. In this paper we have used radar data to examine and substantiate the cloud burst that led to these torrential rains over Chennai and adjoining areas during the Northeast Monsoon period, 2015.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127533592","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