scholarly journals Validation and Error Estimation of AIRS MUSES CO Profiles with HIPPO, ATom and NOAA GML Aircraft Observations

2021 ◽  
Author(s):  
Jennifer D. Hegarty ◽  
Karen E. Cady-Pereira ◽  
Vivienne H. Payne ◽  
Susan S. Kulawik ◽  
John R. Worden ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Optimal Estimation ◽  
Reference Network ◽  
Atmospheric Infrared Sounder ◽  
Tropical Regions ◽  
Mixing Ratios ◽  
Bias Drift ◽  
Time Period ◽  
Aircraft Observations ◽  
Standard Deviations

Abstract. Single footprint retrievals of carbon monoxide from the Atmospheric Infrared Sounder (AIRS) are evaluated using aircraft in situ observations. The aircraft data are from the HIAPER Pole-to-Pole (HIPPO, 2009–2011), the first three Atmospheric Tomography Mission (ATom, 2016–2017) campaigns and the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) Global Greenhouse Gas Reference Network Aircraft Program from 2006–2017. The retrievals are obtained using an optimal estimation approach within the MUlti-SpEctra, MUlti-SpEcies, MUlti-Sensors (MUSES) algorithm. Retrieval biases and estimated errors are evaluated across a range of latitudes from the sub-polar to tropical regions over both ocean and land points. AIRS MUSES CO profiles were compared with HIPPO, ATom, and NOAA GML aircraft observations with a coincidence of 9 hours and 50 km to estimate retrieval biases and standard deviations. Comparisons were done for different pressure levels and column averages, latitudes, day, night, land, and ocean observations. We find mean biases of +6.6 % +/− 4.6 %, +0.6 % +/− 3.2 %, −6.1 % +/− 3.0 %, and 1.4 % +/− 3.6 %, for 750 hPa, 510 hPa, 287 hPa, and the column averages, respectively. The mean standard deviation is 15 %, 11 %, 12 %, and 9 % at these same pressure levels, respectively. Observation errors (theoretical errors) from the retrievals were found to be broadly consistent in magnitude with those estimated empirically from ensembles of satellite aircraft comparisons. The GML Aircraft Program comparisons generally had higher standard deviations and biases than the HIPPO and ATom comparisons. Since the GML aircraft flights do not go as high as the HIPPO and ATom flights, results from these GML comparisons are more sensitive to the choice of method for extrapolation of the aircraft profile above the uppermost measurement altitude. The AIRS retrieval performance shows little sensitivity to surface type (land or ocean) or day or night but some sensitivity to latitude. Comparisons to the NOAA GML set spanning the years 2006–2017 show that the AIRS retrievals are able to capture the distinct seasonal cycles but show a high bias of ~20 % in the lower troposphere during the summer when observed CO mixing ratios are at annual minimum values. The retrieval bias drift was examined over the same period and found to be small at < 0.5 % over the 2006–2017 time period.

scholarly journals Comparison of AIRS and IASI Radiances Using GOES Imagers as Transfer Radiometers toward Climate Data Records

2010 ◽  
Vol 49 (3) ◽  
pp. 478-492 ◽  
Author(s):  
Likun Wang ◽  
Xiangqian Wu ◽  
Mitch Goldberg ◽  
Changyong Cao ◽  
Yaping Li ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Climate Data ◽  
Atmospheric Infrared Sounder ◽  
Mean Values ◽  
Tropical Regions ◽  
Time Period ◽  
Double Differences ◽  
Cross Track ◽  
Spectral Channels

Abstract The Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI), together with the future Cross-track Infrared Sounder, will provide long-term hyperspectral measurements of the earth and its atmosphere at ∼10 km spatial resolution. Quantifying the radiometric difference between AIRS and IASI is crucial for creating fundamental climate data records and establishing the space-based infrared calibration standard. Since AIRS and IASI have different local equator crossing times, a direct comparison of these two instruments over the tropical regions is not feasible. Using the Geostationary Operational Environmental Satellite (GOES) imagers as transfer radiometers, this study compares AIRS and IASI over warm scenes in the tropical regions for a time period of 16 months. The double differences between AIRS and IASI radiance biases relative to the GOES-11 and -12 imagers are used to quantify the radiance differences between AIRS and IASI within the GOES imager spectral channels. The results indicate that, at the 95% confidence level, the mean values of the IASI − AIRS brightness temperature differences for warm scenes are very small, that is, −0.0641 ± 0.0074 K, −0.0432 ± 0.0114 K, and −0.0095 ± 0.0151 K for the GOES-11 6.7-, 10.7-, and 12.0-μm channels, respectively, and −0.0490 ± 0.0100 K, −0.0419 ± 0.0224 K, and −0.0884 ± 0.0160 K for the GOES-12 6.5-, 10.7-, and 13.3-μm channels, respectively. The brightness temperature biases between AIRS and IASI within the GOES imager spectral range are less than 0.1 K although the AIRS measurements are slightly warmer than those of IASI.

scholarly journals Phosgene in the UTLS: seasonal and latitudinal variations from MIPAS observations

2016 ◽  
Author(s):  
Massimo Valeri ◽  
Massimo Carlotti ◽  
Jean-Marie Flaud ◽  
Piera Raspollini ◽  
Marco Ridolfi ◽  
...  
Keyword(s):  
Michelson Interferometer ◽  
Emission Spectra ◽  
Optimal Estimation ◽  
Polar Regions ◽  
Tropical Regions ◽  
Mixing Ratios ◽  
Retrieval Technique ◽  
Vertical Distributions ◽  
Latitudinal Variations ◽  
Polar Orbiting Satellite

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a Fourier Transform Spectrometer that measured mid-infrared atmospheric limb emission spectra from July 2002 to April 2012 on board the polar-orbiting satellite ENVISAT. We have used MIPAS data to study the latitudinal variations of phosgene (COCl2 or carbonyl chloride) and, for the first time, its seasonal variation in the upper troposphere lower stratosphere region (UTLS). Retrievals of phosgene were made using the 830–860 cm−1 region, corresponding to the ν5 bands of COCl2. Unfortunately in that region the ν4 band of CFC-11, much stronger than COCl2 ν5, hides the phosgene emission. In order to evaluate seasonality and latitudinal distribution of phosgene we have analysed all the measurements made by MIPAS in the days 18 and 20 of each month of 2008 with the Optimized Retrieval Model (ORM) recently upgraded with the Multi-Target Retrieval technique and with the Optimal Estimation functionality to apply external constraints to the state vector. Average seasonal profiles of phosgene show an evident latitudinal variability with the largest values observed in the tropical regions (maximum ≈ 35 parts per trillion by volume (pptv) at about 300 hPa). In the mid-latitude and polar regions, the volume mixing ratios (VMR) values do not exceed 30 pptv and the vertical distributions are less peaked. Our analysis highlights that COCl2 seasonal variability is fairly low, apart from the polar regions.

scholarly journals First results from the GPS atmosphere sounding experiment TOR aboard the TerraSAR-X satellite

2011 ◽  
Vol 11 (13) ◽  
pp. 6687-6699 ◽  
Author(s):  
G. Beyerle ◽  
L. Grunwaldt ◽  
S. Heise ◽  
W. Köhler ◽  
R. König ◽  
...  
Keyword(s):  
Closed Loop ◽  
Processing System ◽  
Lower Troposphere ◽  
Open Loop ◽  
Signal Tracking ◽  
Time Period ◽  
Low Latitudes ◽  
First Results ◽  
Standard Deviations ◽  
Data Yield

Abstract. GPS radio occultation events observed between 24 July and 17 November 2008 by the IGOR occultation receiver aboard the TerraSAR-X satellite are processed and analyzed. The comparison of 15 327 refractivity profiles with collocated ECMWF data yield a mean bias between zero and −0.30 % at altitudes between 5 and 30 km. Standard deviations decrease from about 1.4 % at 5 km to about 0.6 % at 10 km altitude, however, increase significantly in the upper stratosphere. At low latitudes mean biases and standard deviations are larger, in particular in the lower troposphere. The results are consistent with 15 159 refractivity observations collected during the same time period by the BlackJack receiver aboard GRACE-A and processed by GFZ's operational processing system. The main difference between the two occultation instruments is the implementation of open-loop signal tracking in the IGOR (TerraSAR-X) receiver which improves the tropospheric penetration depth in terms of ray height by about 2 km compared to the conventional closed-loop data acquired by BlackJack (GRACE-A).

scholarly journals First results from the GPS atmosphere sounding experiment TOR aboard the TerraSAR-X satellite

2010 ◽  
Vol 10 (11) ◽  
pp. 28821-28857 ◽  
Author(s):  
G. Beyerle ◽  
L. Grunwaldt ◽  
S. Heise ◽  
W. Köhler ◽  
R. König ◽  
...  
Keyword(s):  
Closed Loop ◽  
Processing System ◽  
Lower Troposphere ◽  
Open Loop ◽  
Signal Tracking ◽  
Time Period ◽  
Low Latitudes ◽  
First Results ◽  
Standard Deviations ◽  
Data Yield

Abstract. GPS radio occultation events observed between 24 July and 17 November 2008 by the IGOR occultation receiver aboard the TerraSAR-X satellite are processed and analyzed. The comparison of 16 262 refractivity profiles with collocated ECMWF data yield a mean bias of −0.60% to +0.02% at altitudes between 5 and 30 km. Standard deviations decrease from about 0.8% to 1.8% at 5 km to about 0.5% to 0.8% at about 10 km altitude. At low latitudes mean biases and standard deviations are larger, in particular in the lower troposphere. The results are consistent with 15 159 refractivity observations collected during the same time period by the BlackJack receiver aboard GRACE-A and processed by GFZ's operational processing system. The main difference between the two occultation instruments is the implementation of open-loop signal tracking in the IGOR (TerraSAR-X) receiver which improves the tropospheric penetration depth in terms of ray height by about 2 km compared to the conventional closed-loop data acquired by BlackJack (GRACE-A).

scholarly journals Comparison of Optimal Estimation HDO/H2O Retrievals from AIRS with ORACLES measurements

2019 ◽  
Author(s):  
Robert L. Herman ◽  
John Worden ◽  
David Noone ◽  
Dean Henze ◽  
Kevin Bowman ◽  
...  
Keyword(s):  
A Priori ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Deuterium Content ◽  
Aircraft Measurements ◽  
State University ◽  
Atmospheric Infrared Sounder ◽  
Fractional Deviation ◽  
Oregon State University

Abstract. In this paper we evaluate new retrievals of the deuterium content of water vapor from the Aqua Atmospheric InfraRed Sounder (AIRS) with aircraft measurements of HDO and H2O from the ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) field mission. Single footprint AIRS radiances are processed with an optimal estimation algorithm that provides a vertical profile of the HDO/H2O ratio, characterized uncertainties, and instrument operators (or averaging kernel matrix). These retrievals are compared to vertical profiles of the HDO/H2O from the Oregon State University Water Isotope Spectrometer for Precipitation and Entrainment Research (WISPER) on the ORACLES NASA P-3B Orion aircraft. Measurements were taken over the Southeast Atlantic Ocean from 31 August to 25 September 2016. HDO/H2O is commonly reported in delta-D notation, which is the fractional deviation of the HDO/H2O ratio from the standard reference ratio. For collocated measurements, the satellite operator (averaging kernels and a priori constraint) is applied to the aircraft profile measurements. We find that AIRS delta-D bias relative to the aircraft is well within the estimated measurement uncertainty. In the lower troposphere, 1000 to 800 hPa, AIRS delta-D bias is −6.6‰ and the Root Mean Square (RMS) deviation is 20.9‰, consistent with the calculated uncertainty of 19.1‰. In the mid-troposphere, 800 to 500 hPa, AIRS delta-D bias is 6.8‰ and RMS 44.9‰, comparable to the calculated uncertainty of 25.8‰.

scholarly journals Improved agreement of AIRS tropospheric carbon monoxide products with other EOS sensors using optimal estimation retrievals

2010 ◽  
Vol 10 (5) ◽  
pp. 11851-11883
Author(s):  
J. X. Warner ◽  
Z. Wei ◽  
L. L. Strow ◽  
C. D. Barnet ◽  
L. C. Sparling ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Degrees Of Freedom ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Primary Objective ◽  
Retrieval Algorithm ◽  
Atmospheric Infrared Sounder ◽  
Error Covariance ◽  
Transport Experiment ◽  
Northern Pacific

Abstract. We present in this paper an alternative retrieval algorithm for the Atmospheric Infrared Sounder (AIRS) tropospheric Carbon Monoxide (CO) products using the Optimal Estimation (OE) technique, which is different from AIRS operational algorithm. The primary objective for this study was to compare AIRS CO, as well as the other retrieval properties such as the Averaging Kernels (AKs), the Degrees of Freedom for Signal (DOFS), and the error covariance matrix, against the Tropospheric Emission Spectrometer (TES) and the Measurement of Pollution in the Troposphere (MOPITT) CO, which were also derived using OE technique. We also demonstrate that AIRS OE CO results are much more realistic than AIRS V5 operational CO, especially in the lower troposphere and in the Southern Hemisphere (SH). These products are validated with in situ profiles obtained by the Differential Absorption Carbon Monoxide Measurements (DACOM), which took place as part of NASA's Intercontinental Chemical Transport Experiment (INTEX-B) field mission that was conducted over the northern Pacific in Spring 2006. To demonstrate the differences existing in the current operational products we first show a detailed direct comparison between AIRS V5 and TES operational V3 CO for the global datasets from December 2005 to July 2008. We then present global CO comparisons between AIRS OE, TES V3, and MOPITT V4 at selected levels as well as for the total column amounts.

scholarly journals Comparison of optimal estimation HDO∕H<sub>2</sub>O retrievals from AIRS with ORACLES measurements

2020 ◽  
Vol 13 (4) ◽  
pp. 1825-1834
Author(s):  
Robert L. Herman ◽  
John Worden ◽  
David Noone ◽  
Dean Henze ◽  
Kevin Bowman ◽  
...  
Keyword(s):  
A Priori ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Deuterium Content ◽  
Vertical Profiles ◽  
Aircraft Measurements ◽  
State University ◽  
Atmospheric Infrared Sounder ◽  
Fractional Deviation

Abstract. In this paper we evaluate new retrievals of the deuterium content of water vapor from the Aqua Atmospheric InfraRed Sounder (AIRS), with aircraft measurements of HDO and H2O from the ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) field mission. Single-footprint AIRS radiances are processed with an optimal estimation algorithm that provides vertical profiles of the HDO∕H2O ratio, characterized uncertainties and instrument operators (i.e., averaging kernel matrix). These retrievals are compared to vertical profiles of the HDO∕H2O ratio from the Oregon State University Water Isotope Spectrometer for Precipitation and Entrainment Research (WISPER) on the ORACLES NASA P-3B Orion aircraft. Measurements were taken over the southeastern Atlantic Ocean from 31 August to 25 September 2016. HDO∕H2O is commonly reported in δD notation, which is the fractional deviation of the HDO∕H2O ratio from the standard reference ratio. For collocated measurements, the satellite instrument operator (averaging kernels and a priori constraint) is applied to the aircraft profile measurements. We find that AIRS δD bias relative to the aircraft is well within the estimated measurement uncertainty. In the lower troposphere, 1000 to 800 hPa, AIRS δD bias is −6.6 ‰ and the root-mean-square (rms) deviation is 20.9 ‰, consistent with the calculated uncertainty of 19.1 ‰. In the mid-troposphere, 800 to 500 hPa, AIRS δD bias is −6.8 ‰ and rms 44.9 ‰, comparable to the calculated uncertainty of 25.8 ‰.

scholarly journals Improved agreement of AIRS tropospheric carbon monoxide products with other EOS sensors using optimal estimation retrievals

2010 ◽  
Vol 10 (19) ◽  
pp. 9521-9533 ◽  
Author(s):  
J. X. Warner ◽  
Z. Wei ◽  
L. L. Strow ◽  
C. D. Barnet ◽  
L. C. Sparling ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Degrees Of Freedom ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Primary Objective ◽  
Retrieval Algorithm ◽  
Atmospheric Infrared Sounder ◽  
Error Covariance ◽  
Transport Experiment ◽  
Total Column

Abstract. We present in this paper an alternative retrieval algorithm for the Atmospheric Infrared Sounder (AIRS) tropospheric Carbon Monoxide (CO) products using the Optimal Estimation (OE) technique, which is different from the AIRS operational algorithm. The primary objective for this study was to compare AIRS CO, as well as the other retrieval properties such as the Averaging Kernels (AKs), the Degrees of Freedom for Signal (DOFS), and the error covariance matrix, against the Tropospheric Emission Spectrometer (TES) and the Measurement of Pollution in the Troposphere (MOPITT) CO, which were also derived using the OE technique. We also demonstrate that AIRS OE CO results are much more realistic than AIRS V5 operational CO, especially in the lower troposphere and in the Southern Hemisphere (SH). These products are validated with in situ profiles obtained by the Differential Absorption Carbon Monoxide Measurements (DACOM), which took place as part of NASA's Intercontinental Chemical Transport Experiment (INTEX-B) field mission that was conducted over the northern Pacific in Spring 2006. To demonstrate the differences existing in the current operational products we first show a detailed direct comparison between AIRS V5 and TES operational V3 CO for the global datasets from December 2005 to July 2008. We then present global CO comparisons between AIRS OE, TES V3, and MOPITT V4 at selected pressure levels as well as for the total column amounts. We conclude that the tropospheric CO retrievals from AIRS OE and TES V3 agree to within 5–10 ppbv or 5% on average globally and throughout the free troposphere. The agreements in total column CO amounts between AIRS OE and MOPITT V4 have improved significantly compared to AIRS V5 with global relative RMS differences now being 12.7%.

scholarly journals The Extent of Heat on Health and Sustainable Farming in Ghana –Bawku East

2014 ◽  
Vol 3 (3) ◽  
pp. 56 ◽  
Author(s):  
Frimpong Kwasi ◽  
Jacque Oosthuizen ◽  
Eddie Van Etten
Keyword(s):  
Developing Countries ◽  
Health Effects ◽  
Rural Areas ◽  
High Heat ◽  
Northern Ghana ◽  
Tropical Regions ◽  
Wet Bulb Globe Temperature ◽  
Time Period ◽  
Outdoor Work ◽  
Globe Temperature

<p>Little is known about the health effects of heat in outdoor work and appropriate work and rest schedules for farmers working in developing countries. As temperatures continue to increase in tropical regions, such as Northern Ghana, it is necessary to evaluate how farmers experience and respond to high heat exposures. In this study, WBGT (Wet Bulb Globe Temperature) estimates and the ISO work / rest standards were applied to a cohort of farmers in the rural areas of Bawku East, Northern Ghana, to assess how farmers respond to high heat and how much they rest to protect their health, as well as the level of heat on their productivity. WBGT data was recorded over a period of 6 months among vegetable, cereals, and legume farmers. The ISO proposed and actual rest regimes observed by farmers in the same time period were evaluated. In the dry season the dry bulb temperature rose as high as 45 ºC, while during the humid months of March and April WBGT rose to levels as high as 34 ºC. Farmers worked for nine hours a day during these hot periods with insufficient rest, which has adverse consequences on their health and productivity.</p>

scholarly journals Characterization of Transport Regimes and the Polar Dome during Arctic Spring and Summer using in-situ Aircraft Measurements

2019 ◽  
Author(s):  
Heiko Bozem ◽  
Peter Hoor ◽  
Daniel Kunkel ◽  
Franziska Köllner ◽  
Johannes Schneider ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
High Arctic ◽  
The Arctic ◽  
Trace Gas ◽  
Second Phase ◽  
Aerosol Formation ◽  
Transport Barrier ◽  
Data Set ◽  
Air Masses ◽  
Mixing Ratios

Abstract. The springtime composition of the Arctic lower troposphere is to a large extent controlled by transport of mid-latitude air masses into the Arctic, whereas during the summer precipitation and natural sources play the most important role. Within the Arctic region, there exists a transport barrier, known as the polar dome, which results from sloping isentropes. The polar dome, which varies in space and time, exhibits a strong influence on the transport of air masses from mid-latitudes, enhancing it during winter and inhibiting it during summer. Furthermore, a definition for the location of the polar dome boundary itself is quite sparse in the literature. We analyzed aircraft based trace gas measurements in the Arctic during two NETCARE airborne field camapigns (July 2014 and April 2015) with the Polar 6 aircraft of Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI), Bremerhaven, Germany, covering an area from Spitsbergen to Alaska (134° W to 17° W and 68° N to 83° N). For the spring (April 2015) and summer (July 2014) season we analyzed transport regimes of mid-latitude air masses travelling to the high Arctic based on CO and CO2 measurements as well as kinematic 10-day back trajectories. The dynamical isolation of the high Arctic lower troposphere caused by the transport barrier leads to gradients of chemical tracers reflecting different local chemical life times and sources and sinks. Particularly gradients of CO and CO2 allowed for a trace gas based definition of the polar dome boundary for the two measurement periods with pronounced seasonal differences. For both campaigns a transition zone rather than a sharp boundary was derived. For July 2014 the polar dome boundary was determined to be 73.5° N latitude and 299–303.5 K potential temperature, respectively. During April 2015 the polar dome boundary was on average located at 66–68.5° N and 283.5–287.5 K. Tracer-tracer scatter plots and probability density functions confirm different air mass properties inside and outside of the polar dome for the July 2014 and April 2015 data set. Using the tracer derived polar dome boundaries the analysis of aerosol data indicates secondary aerosol formation events in the clean summertime polar dome. Synoptic-scale weather systems frequently disturb this transport barrier and foster exchange between air masses from midlatitudes and polar regions. During the second phase of the NETCARE 2014 measurements a pronounced low pressure system south of Resolute Bay brought inflow from southern latitudes that pushed the polar dome northward and significantly affected trace gas mixing ratios in the measurement region. Mean CO mixing ratios increased from 77.9 ± 2.5 ppbv to 84.9 ± 4.7 ppbv from the first period to the second period. At the same time CO2 mixing ratios significantly dropped from 398.16 ± 1.01 ppmv to 393.81 ± 2.25 ppmv. We further analysed processes controlling the recent transport history of air masses within and outside the polar dome. Air masses within the spring time polar dome mainly experienced diabatic cooling while travelling over cold surfaces. In contrast air masses in the summertime polar dome were diabatically heated due to insolation. During both seasons air masses outside the polar dome slowly descended into the Arctic lower troposphere from above caused by radiative cooling. The ascent to the middle and upper troposphere mainly took place outside the Arctic, followed by a northward motion. Our results demonstrate the successful application of a tracer based diagnostic to determine the location of the polar dome boundary.

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