scholarly journals Validation of INSAT-3D sounder data with in-situ measurements and other similar satellite observations over Indian region

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
A. Hemanth Kumar ◽  
A. Jayaraman
Keyword(s):  
Water Vapor ◽  
Lower Troposphere ◽  
India Meteorological Department ◽  
Analysis Data ◽  
Infrared Region ◽  
In Situ Measurements ◽  
Indian Region ◽  
Positive Bias ◽  
3D Data

Abstract. To date, several satellites measurements are available which can provide profiles of temperature and water vapor with reasonable accuracies. However, temporal resolution remained poor, particularly over topics, as most of them are polar orbiting. At this juncture, launch of INSAT-3D (Indian National Satellite) by the Indian Space Research Organization (ISRO) on 26 July 2013 carrying multi-spectral imager covering visible to long wave infrared region made it possible to obtain profiles of temperature and water vapor over Indian region with higher temporal and vertical resolutions and altitude coverage besides the other parameters. The initial validation of INSAT-3D data is made with the high temporal (3 h) resolution radiosonde observations launched over Gadanki (13.5° N, 79.2° E) during a special campaign and routine evening soundings obtained at 12 UTC. We also compared INSAT-3D data with the radiosonde observations obtained from 34 India Meteorological Department stations. Comparisons were also made over Indian region with data from other satellites like AIRS, MLS and SAPHIR and ERA-Interim and NCEP re-analysis datasets. INSAT-3D is able to show a better coverage over Indian region with high spatial and temporal resolutions as expected. Good correlation in temperature between INSAT-3D and in-situ measurements is noticed except in the upper troposphere and lower stratospheric region (positive bias of 2–3 K). There exists mean dry bias of 10–25 % in relative humidity. Similar biases are also noticed when compared to other satellites and re-analysis data sets. INSAT-3D shows large positive bias in temperature above 25° N in the lower troposphere. Thus, caution is advised in using this data at those places for tropospheric studies. Finally it is concluded that temperature data from INSAT-3D is of high quality that can be directly assimilated for better forecast over Indian region.

scholarly journals Validation of INSAT-3D sounder data with in situ measurements and other similar satellite observations over India

2016 ◽  
Vol 9 (12) ◽  
pp. 5735-5745 ◽  
Author(s):  
Madineni Venkat Ratnam ◽  
Alladi Hemanth Kumar ◽  
Achuthan Jayaraman
Keyword(s):  
Water Vapour ◽  
Lower Troposphere ◽  
India Meteorological Department ◽  
Satellite System ◽  
Reanalysis Data ◽  
In Situ Measurements ◽  
Data Sets ◽  
Positive Bias ◽  
3D Data

Abstract. To date, several satellites measurements are available which can provide profiles of temperature and water vapour with reasonable accuracies. However, the temporal resolution has remained poor, particularly over the tropics, as most of them are polar orbiting. At this juncture, the launch of INSAT-3D (Indian National Satellite System) by the Indian Space Research Organization (ISRO) on 26 July 2013 carrying a multi-spectral imager covering visible to long-wave infrared made it possible to obtain profiles of temperature and water vapour over India with higher temporal and vertical resolutions and altitude coverage, besides other parameters. The initial validation of INSAT-3D data is made with the high temporal (3 h) resolution radiosonde observations launched over Gadanki (13.5° N, 79.2° E) during a special campaign and routine evening soundings obtained at 12:00 UTC (17:30 LT). We also compared INSAT-3D data with the radiosonde observations obtained from 34 India Meteorological Department stations. Comparisons were also made over India with data from other satellites like AIRS, MLS and SAPHIR and from ERA-Interim and NCEP reanalysis data sets. INSAT-3D is able to show better coverage over India with high spatial and temporal resolutions as expected. Good correlation in temperature between INSAT-3D and in situ measurements is noticed except in the upper tropospheric and lower stratospheric regions (positive bias of 2–3 K). There is a mean dry bias of 20–30 % in the water vapour mixing ratio. Similar biases are noticed when compared to other satellites and reanalysis data sets. INSAT-3D shows a large positive bias in temperature above 25° N in the lower troposphere. Thus, caution is advised when using these data for tropospheric studies. Finally it is concluded that temperature data from INSAT-3D are of high quality and can be directly assimilated for better forecasts over India.

scholarly journals Aircraft validation of Aura Tropospheric Emission Spectrometer retrievals of HDO / H<sub>2</sub>O

2014 ◽  
Vol 7 (9) ◽  
pp. 3127-3138 ◽  
Author(s):  
R. L. Herman ◽  
J. E. Cherry ◽  
J. Young ◽  
J. M. Welker ◽  
D. Noone ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Standard Deviation ◽  
Lower Troposphere ◽  
Temporal Variations ◽  
Observation Error ◽  
Free Troposphere ◽  
Data Set ◽  
Airborne Measurements

Abstract. The EOS (Earth Observing System) Aura Tropospheric Emission Spectrometer (TES) retrieves the atmospheric HDO / H2O ratio in the mid-to-lower troposphere as well as the planetary boundary layer. TES observations of water vapor and the HDO isotopologue have been compared with nearly coincident in situ airborne measurements for direct validation of the TES products. The field measurements were made with a commercially available Picarro L1115-i isotopic water analyzer on aircraft over the Alaskan interior boreal forest during the three summers of 2011 to 2013. TES special observations were utilized in these comparisons. The TES averaging kernels and a priori constraints have been applied to the in situ data, using version 5 (V005) of the TES data. TES calculated errors are compared with the standard deviation (1σ) of scan-to-scan variability to check consistency with the TES observation error. Spatial and temporal variations are assessed from the in situ aircraft measurements. It is found that the standard deviation of scan-to-scan variability of TES δD is ±34.1‰ in the boundary layer and ± 26.5‰ in the free troposphere. This scan-to-scan variability is consistent with the TES estimated error (observation error) of 10–18‰ after accounting for the atmospheric variations along the TES track of ±16‰ in the boundary layer, increasing to ±30‰ in the free troposphere observed by the aircraft in situ measurements. We estimate that TES V005 δD is biased high by an amount that decreases with pressure: approximately +123‰ at 1000 hPa, +98‰ in the boundary layer and +37‰ in the free troposphere. The uncertainty in this bias estimate is ±20‰. A correction for this bias has been applied to the TES HDO Lite Product data set. After bias correction, we show that TES has accurate sensitivity to water vapor isotopologues in the boundary layer.

Enhancing WRF Model Forecasts by Assimilating High-Resolution GPS-Derived Water-Vapor Maps combined with METEOSAT-11 Data 

2021 ◽  
Author(s):  
Yuval Reuveni ◽  
Anton Leontiev ◽  
Dorita Rostkier-Edelstein
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Numerical Models ◽  
Eastern Mediterranean ◽  
Wrf Model ◽  
In Situ Measurements ◽  
Suggested Approach ◽  
Positioning Systems ◽  
The Mediterranean

&lt;p&gt;Improving the accuracy of numerical weather predictions still poses a challenging task. The lack of sufficiently detailed spatio-temporal real-time in-situ measurements constitutes a crucial gap concerning the adequate representation of atmospheric moisture fields, such as water vapor, which are critical for improving weather predictions accuracy. Information on total vertically integrated water vapor (IWV), extracted from global positioning systems (GPS) tropospheric path delays, can enhance various atmospheric models at global, regional, and local scales. Currently, numerous existing atmospheric numerical models predict IWV. Nevertheless, they do not provide accurate estimations compared with in-situ measurements such as radiosondes. In this work, we demonstrate a novel approach for assimilating 2D IWV regional maps estimations, extracted from GPS tropospheric path delays combined with METEOSAT satellite imagery data, to enhance Weather Research and Forecast (WRF) model predictions accuracy above the Eastern Mediterranean area. Unlike previous studies, which assimilated IWV point measurements, here, we assimilate quasi-continuous 2D GPS IWV maps, augmented by METEOSAT-11 data, over Israel and its surroundings. Using the suggested approach, our results show a decrease of more than 30% in the root mean square error (RMSE) of WRF forecasts after assimilation relative to the standalone WRF when verified against in-situ radiosonde measurements near the Mediterranean coast. Furthermore, substantial improvements along the Jordan Rift Valley and Dead Sea Valley areas are achieved when compared to 2D IWV regional maps. Improvements in these areas suggest the importance of the assimilated high resolution IWV maps, in particular when assimilation and initialization times coincide with the Mediterranean Sea Breeze propagation from the coastline to highland stations.&lt;/p&gt;

Vertical distribution of aerosol particles over the Russian Arctic derived from in-situ aircraft measurements: the September 2020 campaign

2021 ◽  
Author(s):  
Mikhail Yu. Arshinov ◽  
Boris Belan ◽  
Denis Davydov ◽  
Artem Kozlov ◽  
Alexandr Fofonov
Keyword(s):  
Vertical Distribution ◽  
Lower Troposphere ◽  
In Situ Measurements ◽  
The Arctic ◽  
Future Climate Change ◽  
Russian Arctic ◽  
Size Distributions ◽  
Cloudy Weather ◽  
Wide Range

&lt;p&gt;The Arctic is warming much faster than other regions of the globe. In 2020, temperature anomalies in the Russian Arctic reached unprecedented high levels. The atmospheric composition in this key region still remains insufficiently studied that makes difficult predicting future climate change.&lt;/p&gt;&lt;p&gt;In September 2020, an extensive aircraft campaign was conducted to document the tropospheric composition over the Russian Arctic. The Optik Tu-134 research aircraft was equipped with instruments to carry out in-situ measurements of trace gases and aerosols, as well as with a lidar for profiling of aerosol backscatter. The aircraft flew over a vast area from Arkhangelsk to Anadyr. Six measurement flights with changing altitudes from 0.2 to 9.0 m were conducted over the waters of the Barents, Kara, Laptev, East Siberian, Chukchi, and Bering Seas. The weather was unusually warm for this period of the year, surface air temperatures were above 0&amp;#176;C through the campaign.&lt;/p&gt;&lt;p&gt;Here, we present the results of in-situ measurements of the vertical distribution of aerosol number concentrations in a wide range of sizes. A modified diffusional particle sizer (DPS) consisted of the Novosibirsk-type eight-stage screen diffusion battery connected to the TSI condensation particle counter Model 3756 was used to determine the number size distribution of particles between 0.003 mm and 0.2 mm (20 size bins). Distribution of particles in the size range from 0.25 &amp;#181;m to 32 &amp;#181;m (31 size bins) was measured by means of the Grimm aerosol spectrometer Model 1.109.&lt;/p&gt;&lt;p&gt;The flights over Barents and Kara Seas were predominantly performed under clear sky or partly cloudy weather conditions. Number size distributions were wide representing particles of almost all aerosol fractions. When flying in the upper troposphere with a constant altitude over these seas, some cases of enhanced concentrations of nucleation and Aitken mode particles comparable to ones in the lower troposphere were recorded, suggesting in situ new particle formation was likely to be taking place via gas-to-particle conversion aloft.&lt;/p&gt;&lt;p&gt;East of the Kara Sea, flights were conducted under mostly cloudy conditions resulting in a lower median aerosol number concentration and narrower size distributions.&lt;/p&gt;&lt;p&gt;This work was supported by the Russian Foundation for Basic Research (Grant No. 19-05-50024).&lt;/p&gt;

scholarly journals Remote sensed and in situ constraints on processes affecting tropical tropospheric ozone

2006 ◽  
Vol 6 (6) ◽  
pp. 11465-11520 ◽  
Author(s):  
B. Sauvage ◽  
R. V. Martin ◽  
A. van Donkelaar ◽  
X. Liu ◽  
K. Chance ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Tropospheric Ozone ◽  
Transport Model ◽  
Lower Troposphere ◽  
In Situ Measurements ◽  
Top Down ◽  
Upper Troposphere ◽  
In Situ Observations ◽  
Tropospheric O3

Abstract. We use a global chemical transport model (GEOS-Chem) to evaluate the consistency of satellite measurements of lightning flashes and ozone precursors with in situ measurements of tropical tropospheric ozone. The measurements are tropospheric O3, NO2, and HCHO columns from the GOME satellite instrument, lightning flashes from the OTD and LIS instruments, profiles of O3, CO, and relative humidity from the MOZAIC aircraft program, and profiles of O3 from the SHADOZ ozonesonde network. We interpret these multiple data sources with our model to better understand what controls tropical tropospheric ozone. Tropical tropospheric ozone is mainly affected by lightning and convection in the upper troposphere and by surface emissions in the lower troposphere. Scaling the spatial distribution of lightning in the model to the observed flash counts improves the simulation of O3 in the upper troposphere by 5–20 ppbv versus in situ observations and by 1–4 Dobson Units versus GOME retrievals of tropospheric O3 columns. A lightning source strength of 5±2 Tg N/yr best represents in situ observations from aircraft and ozonesonde. Tropospheric NO2 and HCHO columns from GOME are applied to provide top-down constraints on emission inventories of NOx (biomass burning and soils) and VOCs (biomass burning). The top-down biomass burning inventory is larger by a factor of 2 for HCHO and alkenes, and by 2.6 for NOx over northern equatorial Africa. These emissions increase lower tropospheric O3 by 5–20 ppbv, improving the simulation versus aircraft observations, and by 4 Dobson Units versus GOME observations of tropospheric O3 columns. Emission factors in the a posteriori inventory are more consistent with a recent compilation from in situ measurements. The ozone simulation using two different dynamical schemes (GEOS-3 and GEOS-4) is evaluated versus observations; GEOS-4 better represents O3 observations by 5–15 ppbv due to enhanced convective detrainment in the upper troposphere. Heterogeneous uptake of HNO3 on aerosols reduces simulated O3 by 5–7 ppbv, reducing a model bias versus in situ observations over and downwind of deserts. Exclusion of HO2 uptake on aerosols improves O3 by 5 ppbv in biomass burning regions.

scholarly journals Constraints on the seasonal cycle of stratospheric water vapor using in situ measurements from the ER-2 and a CO photochemical clock

2001 ◽  
Vol 106 (D19) ◽  
pp. 22707-22724 ◽  
Author(s):  
E. M. Weinstock ◽  
E. J. Hintsa ◽  
D. B. Kirk-Davidoff ◽  
J. G. Anderson ◽  
A. E. Andrews ◽  
...  
Keyword(s):  
Water Vapor ◽  
Seasonal Cycle ◽  
In Situ Measurements ◽  
Stratospheric Water Vapor

scholarly journals Comparison of Fast In situ Stratospheric Hygrometer (FISH) measurements of water vapor in the upper troposphere and lower stratosphere (UTLS) with ECMWF (re)analysis data

2014 ◽  
Vol 14 (19) ◽  
pp. 10803-10822 ◽  
Author(s):  
A. Kunz ◽  
N. Spelten ◽  
P. Konopka ◽  
R. Müller ◽  
R. M. Forbes ◽  
...  
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Analysis Data ◽  
Large Set ◽  
Mixing Ratio ◽  
Perfect Agreement ◽  
Upper Troposphere ◽  
Time Periods ◽  
Water Vapor Mixing Ratio

Abstract. An evaluation of water vapor in the upper troposphere and lower stratosphere (UTLS) of the ERA-Interim, the global atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), is presented. Water vapor measurements are derived from the Fast In situ Stratospheric Hygrometer (FISH) during a large set of airborne measurement campaigns from 2001 to 2011 in the tropics, midlatitudes and polar regions, covering isentropic layers from 300 to 400K (5–18km). The comparison shows around 87% of the reanalysis data are within a factor of 2 of the FISH water vapor measurements and around 30% have a nearly perfect agreement with an over- and underestimation lower than 10%. Nevertheless, strong over- and underestimations can occur both in the UT and LS, in particularly in the extratropical LS and in the tropical UT, where severe over- and underestimations up to 10 times can occur. The analysis data from the evolving ECMWF operational system is also evaluated, and the FISH measurements are divided into time periods representing different cycles of the Integrated Forecast System (IFS). The agreement with FISH improves over the time, in particular when comparing water vapor fields for time periods before 2004 and after 2010. It appears that influences of tropical tropospheric and extratropical UTLS processes, e.g., convective and quasi-isentropic exchange processes, are particularly challenging for the simulation of the UTLS water vapor distribution. Both the reanalysis and operational analysis data show the tendency of an overestimation of low water vapor mixing ratio (&amp;lessapprox;10ppmv) in the LS and underestimation of high water vapor mixing ratio (&amp;gtrapprox;300ppmv) in the UT.

scholarly journals Summertime Moisture Transport to the Southern South American Altiplano: Constraints from In Situ Measurements of Water Vapor Isotopic Composition

2015 ◽  
Vol 28 (7) ◽  
pp. 2635-2649 ◽  
Author(s):  
Joseph Galewsky ◽  
Kimberly Samuels-Crow
Keyword(s):  
Water Vapor ◽  
Isotopic Composition ◽  
Austral Summer ◽  
Dry Season ◽  
In Situ Measurements ◽  
South American ◽  
Moist Air ◽  
Wet Season ◽  
Rayleigh Distillation

Abstract Austral summer transport of water vapor to the southern South American Altiplano is investigated using in situ measurements of water vapor isotopic composition collected from 1 November 2012 to 10 February 2013 on the Chajnantor Plateau in the Chilean Andes. Onset of the wet season in December was associated with an increase in mixing ratios from an average of 1500 ppmv during the winter dry season to 5400 ppmv in early December. Water vapor isotopes δD and δ18O increased from dry season averages of −235‰ and −31‰, respectively, to wet season averages of −142‰ and −17‰, reaching as high as −70‰ and −17‰, respectively. The highest water vapor δ values were close to those measured in coastal settings, suggesting little condensation during transport to the site. About 5% of the wet season data have δ values that are lower than expected for Rayleigh distillation and are associated with high relative humidity (&gt;75%), easterly winds, and periods of low outgoing longwave radiation over the Altiplano, consistent with moistening by deep convection. The remainder of the data have δ values that are greater than expected for Rayleigh distillation, up to 250‰ above the Rayleigh curve. These data are consistent with mixing between very dry air and moist air from the boundary layer. The data show intraseasonal variability coherently linked to the position of the Bolivian high, with moist air associated with a southward displacement in the Bolivian high. The humidity over the southern Altiplano during the wet season reflects a balance among advective drying, advective moistening with little condensation, and convective moistening.

scholarly journals CRISTA-NF measurements during the AMMA-SCOUT-O3 aircraft campaign

2010 ◽  
Vol 3 (5) ◽  
pp. 1437-1455 ◽  
Author(s):  
K. Weigel ◽  
M. Riese ◽  
L. Hoffmann ◽  
S. Hoefer ◽  
C. Kalicinsky ◽  
...  
Keyword(s):  
Infrared Region ◽  
In Situ Measurements ◽  
Temperature Fields ◽  
Research Aircraft ◽  
High Vertical Resolution ◽  
Horizontal Variations ◽  
Temperature Water ◽  
Better Than ◽  
Russian Research

Abstract. The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere – New Frontiers (CRISTA-NF) instrument participated in the AMMA-SCOUT-O3 measurement campaign in July and August 2006. The instrument is mounted on the high-flying Russian research aircraft M55-Geophysica and measures limb-emissions in the mid-infrared region in the tangent altitude range of about 6 to 21 km. We present a new retrieval setup which is based on 9 integrated spectral windows allowing to retrieve an extended set of trace gases and temperature fields with high vertical resolution (up to 500 m). Retrieval results are shown for temperature, water vapor (H2O), ozone (O3), nitric acid (HNO3), peroxyacetyl nitrate (PAN), carbon tetrachloride (CCl4), and aerosol extinction. Comparisons of temperature, O3, and H2O observations with corresponding in situ measurements on-board M55-Geophysica show reasonable agreement. In particular, CRISTA-NF observations in the vicinity of the aircraft resemble horizontal variations found in the in situ measurements better than corresponding ECMWF fields.

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