scholarly journals An improved cirrus detection algorithm MeCiDA2 for SEVIRI and its evaluation with MODIS

2013 ◽  
Vol 6 (2) ◽  
pp. 309-322 ◽  
Author(s):  
F. Ewald ◽  
L. Bugliaro ◽  
H. Mannstein ◽  
B. Mayer
Keyword(s):  
Optical Properties ◽  
Stratospheric Ozone ◽  
Detection Algorithm ◽  
Global Scale ◽  
Radiation Budget ◽  
Viewing Angle ◽  
Imaging Spectrometer ◽  
Infrared Imager ◽  
Moderate Resolution ◽  
Spectrometer Data

Abstract. In this study, a substantially improved version of the Meteosat cirrus detection algorithm (MeCiDA2) will be presented, which now allows application to the full earth disc visible by the Meteosat satellite. As cirrus clouds have an influence on the radiation budget of the earth, their optical properties and their global coverage has to be monitored at the global scale using instruments aboard geostationary satellites. Since MeCiDA was optimised for the area of Europe only, various changes were necessary to handle the variable conditions found over the full Meteosat disc. Required changes include the consideration of the viewing angle dependency and of the sensitivity of the 9.7 μm channel to the ozone column. To this end, a correction is implemented that minimises the influence of the variability of the stratospheric ozone. The evaluation of the proposed improvements is carried out by using MeCiDA applied to MODIS (moderate resolution imaging spectrometer) data to address viewing angle-dependent cirrus detection, and by additionally comparing it to the cloud optical properties MOD06 cirrus product. The new MeCiDA version detects less cirrus than the original one for latitudes larger than 40°, but almost the same amount elsewhere. MeCiDA's version for MODIS is more sensitive than that for SEVIRI (spinning enhanced visible and infrared imager) with cirrus occurrences higher by 10%, and the new MeCiDA provides almost the same cirrus coverage (±0.1) as given by the cloud phase optical properties from MODIS for latitudes smaller than 50°. Finally, the influence of sub-pixel clouds on the SEVIRI cirrus detection has been examined: more than 60% of the undetected SEVIRI cirrus pixels have a cirrus coverage smaller than 0.5.

scholarly journals An improved cirrus detection algorithm MeCiDA2 for SEVIRI and its validation with MODIS

2012 ◽  
Vol 5 (4) ◽  
pp. 5271-5311 ◽  
Author(s):  
F. Ewald ◽  
L. Bugliaro ◽  
H. Mannstein ◽  
B. Mayer
Keyword(s):  
Optical Properties ◽  
Stratospheric Ozone ◽  
Detection Algorithm ◽  
Global Scale ◽  
Cirrus Clouds ◽  
Radiation Budget ◽  
High Temporal Resolution ◽  
Viewing Angle ◽  
Infrared Imager ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. The influence of cirrus clouds on the radiation budget of the Earth depends on their optical properties and their global coverage. The monitoring of cirrus coverage with instruments aboard geostationary satellites enables the investigation of cirrus clouds at the global scale as well as the identification of their diurnal variation. For instance, the Spinning Enhanced Visible and Infrared Imager (SEVIRI) aboard the Meteosat Second Generation (MSG) satellites provides data with high temporal resolution of 15 min and a spatial resolution of 3 km × 3 km at the sub-satellite point. In addition, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the sun-synchronous platforms Terra and Aqua delivers at least one observation per day with a high spatial resolutions ranging from 250 m × 250 m to 1 km × 1 km. Since the infrared channels of the SEVIRI instrument are suitable for an observation which is independent from day-light, Krebs et al. (2007) developed a cirrus detection algorithm for SEVIRI (called MeCiDA), based solely on its thermal channels. Since MeCiDA was optimised for the area of Europe only, we present an improved version of the algorithm which allows application to the full Meteosat disc. Required changes include the consideration of the viewing angle dependency and of the sensitivity of the 9.7 μm channel to the ozone column. To this end, a correction is implemented that minimises the influence of the variability of the stratospheric ozone. The validation of the proposed improvements is carried out by using MeCiDA applied to MODIS data to address viewing angle-dependent cirrus detection and by additionally comparing it to the Cloud Optical Properties MOD06 cirrus product. The new MeCiDA version detects less cirrus than the original one for latitudes larger than 40° but almost the same amount elsewhere. MeCiDA's version for MODIS is more sensitive than that for SEVIRI with cirrus occurrences higher by 10%, and the new MeCiDA provides almost the same cirrus coverage (±0.1) as given by the Cloud Phase Optical Properties from MODIS for latitudes smaller than 50°. Finally, the influence of sub-pixel clouds on the SEVIRI cirrus detection has been examined: more than 60% of the undetected SEVIRI cirrus pixels have a cirrus coverage smaller than 0.5.

scholarly journals Lidar profiling of aerosol optical properties from Paris to Lake Baikal (Siberia)

2015 ◽  
Vol 15 (9) ◽  
pp. 5007-5026 ◽  
Author(s):  
E. Dieudonné ◽  
P. Chazette ◽  
F. Marnas ◽  
J. Totems ◽  
X. Shang
Keyword(s):  
Optical Properties ◽  
Lake Baikal ◽  
Forest Fires ◽  
Western Europe ◽  
Lower Boundary ◽  
Aerosol Optical Properties ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
The Difference ◽  
First Time

Abstract. In June 2013, a ground-based mobile lidar performed the ~10 000 km ride from Paris to Ulan-Ude, near Lake Baikal, profiling for the first time aerosol optical properties all the way from western Europe to central Siberia. The instrument was equipped with N2-Raman and depolarization channels that enabled an optical speciation of aerosols in the low and middle troposphere. The extinction-to-backscatter ratio (also called lidar ratio or LR) and particle depolarization ratio (PDR) at 355 nm have been retrieved. The LR in the lower boundary layer (300–700 m) was found to be 63 ± 17 sr on average during the campaign with a distribution slightly skewed toward higher values that peaks between 50 and 55 sr. Although the difference is small, PDR values observed in Russian cities (>2%, except after rain) are systematically higher than the ones measured in Europe (<1%), which is probably an effect of the lifting of terrigenous aerosols by traffic on roads. Biomass burning layers from grassland or/and forest fires in southern Russia exhibit LR values ranging from 65 to 107 sr and from 3 to 4% for the PDR. During the route, desert dust aerosols originating from the Caspian and Aral seas regions were characterized for the first time, with a LR (PDR) of 43 ± 14 sr (23 ± 2%) for pure dust. The lidar observations also showed that this dust event extended over 2300 km and lasted for ~6 days. Measurements from the Moderate Resolution Imaging Spectrometer (MODIS) show that our results are comparable in terms of aerosol optical thickness (between 0.05 and 0.40 at 355 nm) with the mean aerosol load encountered throughout our route.

scholarly journals Experiments with Cloud Properties: Impact on Surface Radiative Fluxes

2008 ◽  
Vol 25 (6) ◽  
pp. 1034-1040 ◽  
Author(s):  
H. Wang ◽  
R. T. Pinker ◽  
P. Minnis ◽  
M. M. Khaiyer
Keyword(s):  
Optical Properties ◽  
Single Channel ◽  
Winter Season ◽  
Global Scale ◽  
Radiation Budget ◽  
Radiative Fluxes ◽  
Cloud Properties ◽  
Central United States ◽  
Atmospheric Radiation Measurement ◽  
The Impact

Abstract Solar radiation reaching the earth’s surface provides the primary forcing of the climate system, and thus, information on this parameter is needed at a global scale. Several satellite-based estimates of surface radiative fluxes are available, but they differ from each other in many aspects. The focus of this study is to highlight one aspect of such differences, namely, the way satellite-observed radiances are used to derive information on cloud optical properties and the impact this has on derived parameters such as surface radiative fluxes. Frequently, satellite visible radiance in a single channel is used to infer cloud transmission; at times, several spectral channels are utilized to derive cloud optical properties and use these to infer cloud transmission. In this study, an evaluation of these two approaches will be performed in terms of impact on the accuracy in surface radiative fluxes. The University of Maryland Satellite Radiation Budget (UMD/SRB) model is used as a tool to perform such an evaluation over the central United States. The estimated shortwave fluxes are evaluated against ground observations at the Atmospheric Radiation Measurement Program (ARM) Central Facility and at four ARM extended sites. It is shown that the largest differences between these two approaches occur during the winter season when snow is on the ground.

scholarly journals Contrail life cycle and properties from 1 year of MSG/SEVIRI rapid-scan images

2015 ◽  
Vol 15 (15) ◽  
pp. 8739-8749 ◽  
Author(s):  
M. Vázquez-Navarro ◽  
H. Mannstein ◽  
S. Kox
Keyword(s):  
Optical Thickness ◽  
Radiative Forcing ◽  
Detection Algorithm ◽  
Mean Values ◽  
Rapid Scan ◽  
Infrared Imager ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Modis ◽  
Terra Satellite

The automatic contrail tracking algorithm (ACTA) – developed to automatically follow contrails as they age, drift and spread – enables the study of a large number of contrails and the evolution of contrail properties with time. In this paper we present a year's worth of tracked contrails, from August 2008 to July 2009 in order to derive statistically significant mean values. The tracking is performed using the 5 min rapid-scan mode of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) satellites. The detection is based on the high spatial resolution of the images provided by the Moderate Resolution Imaging Spectroradiometer on board the Terra satellite (Terra/MODIS), where a contrail detection algorithm (CDA) is applied. The results show the satellite-derived average lifetimes of contrails and contrail-cirrus along with the probability density function (PDF) of other geometric characteristics such as mean coverage, distribution and width. In combination with specifically developed algorithms (RRUMS; Rapid Retrieval of Upwelling irradiance from MSG/SEVIRI and COCS (Cirrus Optical properties derived from CALIOP and SEVIRI), explained below) it is possible to derive the radiative forcing (RF), energy forcing (EF), optical thickness (τ) and altitude of the tracked contrails. Mean values here retrieved are duration, 1 h; length, 130 km; width, 8 km; altitude, 11.7 km; optical thickness, 0.34. Radiative forcing and energy forcing are shown for land/water backgrounds in day/night situations.

Contrail life cycle and properties from one year of MSG/SEVIRI rapid-scan images

2015 ◽  
Vol 15 (5) ◽  
pp. 7019-7055 ◽  
Author(s):  
M. Vázquez-Navarro ◽  
H. Mannstein ◽  
S. Kox
Keyword(s):  
Optical Thickness ◽  
Radiative Forcing ◽  
Detection Algorithm ◽  
Mean Values ◽  
Rapid Scan ◽  
Infrared Imager ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Modis ◽  
One Year

The Automatic Contrail Tracking Algorithm (ACTA) -developed to automatically follow contrails as they age, drift and spread- enables the study of a large number of contrails and the evolution of contrail properties with time. In this paper we present a year's worth of tracked contrails, from August 2008 to July 2009 in order to derive statistically significant mean values. The tracking is performed using the 5 min rapid-scan mode of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board of the Meteosat Second Generation satellites (MSG). The detection is based on the high spatial resolution of the images provided by the Moderate Resolution Imaging Spectroradiometer on board of the Terra satellite (Terra/MODIS), where a Contrail Detection Algorithm (CDA) is applied. The results show the satellite-derived average lifetimes of contrails and contrail-cirrus along with the probability density function (PDF) of other geometric characteristics such as mean coverage, distribution and width. In combination with specifically developed algorithms (RRUMS and COCS, explained below) it is possible to derive the radiative forcing (RF), energy forcing (EF), optical thickness (τ), and altitude of the tracked contrails. Mean values here retrieved are: duration, 1 h; length, 130 km; width, 8 km; altitude, 11.7 km; optical thickness, 0.34. Radiative forcing and energy forcing are shown for land/water backgrounds in day/night situations.

Impact of aerosol on air temperature in Baghdad

2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Yaseen Kadhim Abbas Al-Timimi ◽  
Ali Challob Khraibet
Keyword(s):  
Temperature Variation ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Air Temperature ◽  
Strong Correlation ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
Resolution Imaging

Aerosol Optical Depth (AOD) is the measure of aerosol distributed with a Column of air from earth’s surface to the top of atmosphere, in this study, temperature variation of aerosol optical depth (AOD) in Baghdad was analyzed Moderate Resolution Imaging Spectrometer (MODIS) from Terra and its relationship with temperature for the period 2003 – 2015 were examined. The highest values for mean seasonal AOD were observed in spring and summer and the maximum AOD values ranged from 0.50 to 0.58 by contrast minimum AOD values ranging from 0.30 to 0.41 were found in winter and autumn. Results of study also showed that the temperature (max., min., mean air temperature and DTR) have a strong correlation with AOD (0.82, 0.83, 0.82 and 0.65) respectively.

scholarly journals A near-global, high resolution land surface parameter dataset for the variable infiltration capacity model

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jacob R. Schaperow ◽  
Dongyue Li ◽  
Steven A. Margulis ◽  
Dennis P. Lettenmaier
Keyword(s):  
Land Surface ◽  
Global Scale ◽  
Radiation Budget ◽  
Soil Parameters ◽  
Variable Infiltration Capacity ◽  
Infiltration Capacity ◽  
Vic Model ◽  
Spatial Coverage ◽  
Land Surface Parameter ◽  
Vegetation Parameters

AbstractHydrologic models predict the spatial and temporal distribution of water and energy at the land surface. Currently, parameter availability limits global-scale hydrologic modelling to very coarse resolution, hindering researchers from resolving fine-scale variability. With the aim of addressing this problem, we present a set of globally consistent soil and vegetation parameters for the Variable Infiltration Capacity (VIC) model at 1/16° resolution (approximately 6 km at the equator), with spatial coverage from 60°S to 85°N. Soil parameters derived from interpolated soil profiles and vegetation parameters estimated from space-based MODIS measurements have been compiled into input files for both the Classic and Image drivers of the VIC model, version 5. Geographical subsetting codes are provided, as well. Our dataset provides all necessary land surface parameters to run the VIC model at regional to global scale. We evaluate VICGlobal’s ability to simulate the water balance in the Upper Colorado River basin and 12 smaller basins in the CONUS, and their ability to simulate the radiation budget at six SURFRAD stations in the CONUS.

scholarly journals DLR HySU—A Benchmark Dataset for Spectral Unmixing

2021 ◽  
Vol 13 (13) ◽  
pp. 2559
Author(s):  
Daniele Cerra ◽  
Miguel Pato ◽  
Kevin Alonso ◽  
Claas Köhler ◽  
Mathias Schneider ◽  
...  
Keyword(s):  
Spectral Unmixing ◽  
Benchmark Dataset ◽  
Data Sets ◽  
Endmember Extraction ◽  
Imaging Spectrometer ◽  
Hyperspectral Unmixing ◽  
Processing Step ◽  
German Aerospace ◽  
Spectrometer Data ◽  
First Time

Spectral unmixing represents both an application per se and a pre-processing step for several applications involving data acquired by imaging spectrometers. However, there is still a lack of publicly available reference data sets suitable for the validation and comparison of different spectral unmixing methods. In this paper, we introduce the DLR HyperSpectral Unmixing (DLR HySU) benchmark dataset, acquired over German Aerospace Center (DLR) premises in Oberpfaffenhofen. The dataset includes airborne hyperspectral and RGB imagery of targets of different materials and sizes, complemented by simultaneous ground-based reflectance measurements. The DLR HySU benchmark allows a separate assessment of all spectral unmixing main steps: dimensionality estimation, endmember extraction (with and without pure pixel assumption), and abundance estimation. Results obtained with traditional algorithms for each of these steps are reported. To the best of our knowledge, this is the first time that real imaging spectrometer data with accurately measured targets are made available for hyperspectral unmixing experiments. The DLR HySU benchmark dataset is openly available online and the community is welcome to use it for spectral unmixing and other applications.

Sign in / Sign up

Export Citation Format

Share Document