On the clouds and ammonia in Jupiter’s upper troposphere from Juno JIRAM reflectivity observations

2021 ◽  
Vol 503 (4) ◽  
pp. 4892-4907
Author(s):  
Davide Grassi ◽  
A Mura ◽  
G Sindoni ◽  
A Adriani ◽  
S K Atreya ◽  
...  
Keyword(s):  
Thermal Emission ◽  
Pressure Level ◽  
Data Set ◽  
Upper Troposphere ◽  
Latitude Range ◽  
Unit Value ◽  
Equatorial Belt ◽  
Modelling Uncertainties ◽  
Diffuse Clouds ◽  
Juno Mission

ABSTRACT We analyse spectra measured by the Jovian Infrared Auroral Mapper (JIRAM, a payload element of the NASA Juno mission) in the 3150–4910 cm−1 (2.0–3.2 μm)  range during the perijiove passage of 2016 August. Despite modelling uncertainties, the quality and the relative uniformity of the data set allow us to determine several parameters characterizing the Jupiter’s upper troposphere in the latitude range of 35°S–30°N. Ammonia relative humidity at 500 millibars varies between 5 per cent to supersaturation beyond 100 per cent for about 3 per cent of the processed spectra. Ammonia appears depleted over belts and relatively enhanced over zones. Local variations of ammonia, arguably associated with local dynamics, are found to occur in several locations on the planet (Oval BA, South Equatorial Belt). Cloud altitude, defined as the level where aerosol opacity reaches unit value at 3650 cm−1 (2.74 μm), is maximum over the Great Red Spot (>20 km  above the 1 bar  level) and the zones (15 km),  while it decreases over the belts and towards higher latitudes. The aerosol opacity scale height suggests more compact clouds over zones and more diffuse clouds over belts. The integrated opacity of clouds above the 1.3-bar pressure level is found to be minimum in regions where thermal emission of the deeper atmosphere is maximum. The opacity of tropospheric haze above the 200-mbar level also increases over zones. Our results are consistent with a Hadley-type circulation scheme previously proposed in literature for belts and zones, with clear hemisphere asymmetries in cloud and haze.

scholarly journals Two decades of in-situ temperature measurements in the upper troposphere and lowermost stratosphere from IAGOS long-term routine observation

2017 ◽  
Author(s):  
Florian Berkes ◽  
Patrick Neis ◽  
Martin G. Schultz ◽  
Ulrich Bundke ◽  
Susanne Rohs ◽  
...  
Keyword(s):  
Weather Forecast ◽  
Global Scale ◽  
Temperature Trend ◽  
Data Set ◽  
Medium Range Weather Forecast ◽  
Upper Troposphere ◽  
Temperature Trends ◽  
Geographical Regions

Abstract. Despite several studies on temperature trends in the tropopause region, a comprehensive understanding of the evolution of temperatures in this climate-sensitive region of the atmosphere remains elusive. Here we present a unique global-scale, long-term data set of high-resolution in-situ temperature data measured aboard passenger aircraft within the European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System, www.iagos.org). This data set is used to investigate temperature trends within the global upper troposphere and lowermost stratosphere (UTLS) for the period 1995 to 2012 in different geographical regions and vertical layers of the UTLS. The largest amount of observations is available over the North Atlantic. Here, a neutral temperature trend is found within the lowermost stratosphere. This contradicts the temperature trend in the European Centre for Medium Range Weather Forecast (ECMWF) ERA-Interim reanalysis, where a significant (95 % confidence) temperature increase of +0.56 K/decade is obtained. Differences between trends derived from observations and reanalysis data can be traced back to changes in the temperature bias between observation and model data over the studied period. This study demonstrates the value of the IAGOS temperature observations as anchor point for the evaluation of reanalyses and its suitability for independent trend analyses.

scholarly journals Climatology and long-term evolution of ozone and carbon monoxide in the UTLS at northern mid-latitudes, as seen by IAGOS from 1995 to 2013

2017 ◽  
Author(s):  
Yann Cohen ◽  
Hervé Petetin ◽  
Valérie Thouret ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Lower Stratosphere ◽  
Boreal Summer ◽  
Brazilian Coast ◽  
Seasonal Cycles ◽  
Western Coast ◽  
Data Set ◽  
Upper Troposphere ◽  
North East ◽  
Wide Range

Abstract. In situ measurements in the upper troposphere – lower stratosphere (UTLS) are performed in the framework of the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System) for ozone since 1994 and for carbon monoxide since 2002. The flight tracks cover a wide range of longitudes in the northern extratropics, extending from the North American western coast (125° W) to the eastern Asian coast (135° E), and more recently over the northern Pacific ocean. Different tropical regions are also sampled frequently, such as the Brazilian coast, central and southern Africa, southeastern Asia and the western Maritime Continent. As a result, a new set of climatologies for O3 (Aug. 1994–Dec. 2013) and CO (Dec. 2001–Dec. 2013) in the upper troposphere (UT), tropopause layer and lower stratosphere (LS) are made available, including quasi-global gridded horizontal distributions, and seasonal cycles over eight well sampled regions of interest in the northern extratropics. The seasonal cycles generally show a summertime maximum in O3 and a springtime maximum in CO in the UT, in contrast with the systematic springtime maximum in O3 and the quasi-absence of seasonal cycle of CO in the LS. This study highlights some regional variabilities in the UT notably (i) a west-east difference of O3 in boreal summer with up to 15 ppb more O3 over central Russia compared with northeast America, (ii) a systematic west-east gradient of CO from 60° E to 140° E (especially noticeable in spring and summer with about 5 ppb by 10 degrees longitude), (iii) a broad spring/summer maximum of CO over North East Asia, and (iv) a spring maximum of O3 over Western North America. Thanks to almost 20 years of O3 and 12 years of CO measurements, the IAGOS database is a unique data set to derive trends in the UTLS. Trends in O3 in the UT are positive and statistically significant in most regions, ranging from +0.25 to +0.45 ppb yr−1, characterized by the significant increase of the lowest values of the distribution. No significant trends of O3 are detected in the LS. Trends of CO in the UT, tropopause and LS are all negative and statistically significant. The estimated slopes range from −1.37 to −0.59 ppb yr−1 , with a nearly homogeneous decrease of the lowest values of the monthly distribution (fifth percentile) contrasting with the high inter-regional variability of the highest values (95th percentile).

scholarly journals River ice flux and water velocities along a 600 km long reach of Lena River, Siberia, from satellite stereo

2013 ◽  
Vol 10 (7) ◽  
pp. 9967-9997 ◽  
Author(s):  
A. Kääb ◽  
M. Lamare ◽  
M. Abrams
Keyword(s):  
River Flow ◽  
Thermal Emission ◽  
Time Lag ◽  
Open Water ◽  
Image Resolution ◽  
Surface Velocity ◽  
River Ice ◽  
Data Set ◽  
Hazard Management ◽  
Lena River

Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstream transport of ice debris is often the most important hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and complete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a time period of about one minute, which is the typical time lag between the two or more images that form a stereo data set in spaceborne, along-track optical stereo-mapping. Using a series of 9 stereo scenes from the US/Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard the NASA Terra spacecraft with 15 m image resolution, we measure the ice and water velocity field over a 620 km long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order image and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 m s−1 from the ASTER data. Maximum ice or water speeds, respectively, reach up to 2.5 m s−1 at the time of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-stream undulations with a wavelength of about 21 km that agree well with variations in channel width and with the location of sand bars along the river reach studied. The methodology and results of this study could be valuable to a number of disciplines requiring detailed information about river flow, such as hydraulics, hydrology, river ecology and natural-hazard management.

scholarly journals Evaluation of water vapour assimilation in the tropical upper troposphere and lower stratosphere by a chemical transport model

2016 ◽  
Vol 9 (9) ◽  
pp. 4355-4373 ◽  
Author(s):  
Swagata Payra ◽  
Philippe Ricaud ◽  
Rachid Abida ◽  
Laaziz El Amraoui ◽  
Jean-Luc Attié ◽  
...  
Keyword(s):  
Water Vapour ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Michelson Interferometer ◽  
Model Space ◽  
Global Scale ◽  
Chemical Transport Model ◽  
Data Set ◽  
Upper Troposphere ◽  
Sensitivity Studies

Abstract. The present analysis deals with one of the most debated aspects of the studies on the upper troposphere/lower stratosphere (UTLS), namely the budget of water vapour (H2O) at the tropical tropopause. Within the French project “Multiscale water budget in the upper troposphere and lower stratosphere in the TROpics” (TRO-pico), a global-scale analysis has been set up based on space-borne observations, models and assimilation techniques. The MOCAGE-VALENTINA assimilation tool has been used to assimilate the Aura Microwave Limb Sounder (MLS) version 3.3 H2O measurements within the 316–5 hPa range from August 2011 to March 2013 with an assimilation window of 1 h. Diagnostics based on observations minus analysis and forecast are developed to assess the quality of the assimilated H2O fields. Comparison with an independent source of H2O measurements in the UTLS based on the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations and with meteorological ARPEGE analyses is also shown. Sensitivity studies of the analysed fields have been performed by (1) considering periods when no MLS measurements are available and (2) using H2O data from another MLS version (4.2). The studies have been performed within three different spaces in time and space coincidences with MLS (hereafter referred to as MLS space) and MIPAS (MIPAS space) observations and with the model (model space) outputs and at three different levels: 121 hPa (upper troposphere), 100 hPa (tropopause) and 68 hPa (lower stratosphere) in January and February 2012. In the MLS space, the analyses behave consistently with the MLS observations from the upper troposphere to the lower stratosphere. In the model space, the analyses are wetter than the reference atmosphere as represented by ARPEGE and MLS in the upper troposphere (121 hPa) and around the tropopause (100 hPa), but are consistent with MLS and MIPAS in the lower stratosphere (68 hPa). In the MIPAS space, the sensitivity and the vertical resolution of the MIPAS data set at 121 and 100 hPa prevent assessment of the behaviour of the analyses at 121 and 100 hPa, particularly over intense convective areas as the South American, the African and the Maritime continents but, in the lower stratosphere (68 hPa), the analyses are very consistent with MIPAS. Sensitivity studies show the improvement on the H2O analyses in the tropical UTLS when assimilating space-borne measurements of better quality, particularly over the convective areas.

scholarly journals Considerations for atmospheric retrieval of high-precision brown dwarf spectra

2020 ◽  
Vol 497 (4) ◽  
pp. 5136-5154
Author(s):  
Anjali A A Piette ◽  
Nikku Madhusudhan
Keyword(s):  
High Precision ◽  
Thermal Emission ◽  
Simulated Data ◽  
Brown Dwarfs ◽  
High Signal ◽  
Temperature Structure ◽  
Wide Field ◽  
Brown Dwarf ◽  
Data Set ◽  
Stellar Objects

ABSTRACT Isolated brown dwarfs provide remarkable laboratories for understanding atmospheric physics in the low-irradiation regime, and can be observed more precisely than exoplanets. As such, they provide a glimpse into the future of high-signal-to-noise ratio (SNR) observations of exoplanets. In this work, we investigate several new considerations that are important for atmospheric retrievals of high-quality thermal emission spectra of sub-stellar objects. We pursue this using an adaptation of the h y dra atmospheric retrieval code. We propose a parametric pressure–temperature (P–T) profile for brown dwarfs consisting of multiple atmospheric layers, parametrized by the temperature change across each layer. This model allows the steep temperature gradient of brown dwarf atmospheres to be accurately retrieved while avoiding commonly encountered numerical artefacts. The P–T model is especially flexible in the photosphere, which can reach a few tens of bar for T-dwarfs. We demonstrate an approach to include model uncertainties in the retrieval, focusing on uncertainties introduced by finite spectral and vertical resolution in the atmospheric model used for retrieval (∼8 per cent in the present case). We validate our retrieval framework by applying it to a simulated data set and then apply it to the HST/WFC3 (Hubble Space Telescope’s Wide-Field Camera 3) spectrum of the T-dwarf 2MASS J2339+1352. We retrieve sub-solar abundances of H2O and CH4 in the object at ∼0.1 dex precision. Additionally, we constrain the temperature structure to within ∼100 K in the photosphere. Our results demonstrate the promise of high-SNR spectra to provide high-precision abundance estimates of sub-stellar objects.

scholarly journals Origin of aerosol particles in the mid-latitude and subtropical upper troposphere and lowermost stratosphere from cluster analysis of CARIBIC data

2009 ◽  
Vol 9 (21) ◽  
pp. 8413-8430 ◽  
Author(s):  
M. Köppe ◽  
M. Hermann ◽  
C. A. M. Brenninkmeijer ◽  
J. Heintzenberg ◽  
H. Schlager ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Cluster Analysis ◽  
Particle Number ◽  
Aerosol Particles ◽  
Free Troposphere ◽  
Data Set ◽  
Upper Troposphere ◽  
Eurasian Continent ◽  
Aitken Mode ◽  
Seasonal Data

Abstract. The origin of aerosol particles in the upper troposphere and lowermost stratosphere over the Eurasian continent was investigated by applying cluster analysis methods to in situ measured data. Number concentrations of submicrometer aerosol particles and trace gas mixing ratios derived by the CARIBIC (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container) measurement system on flights between Germany and South-East Asia were used for this analysis. Four cluster analysis methods were applied to a test data set and their capability of separating the data points into scientifically reasonable clusters was assessed. The best method was applied to seasonal data subsets for summer and winter resulting in five cluster or air mass types: stratosphere, tropopause, free troposphere, high clouds, and boundary layer influenced. Other source clusters, like aircraft emissions could not be resolved in the present data set with the used methods. While the cluster separation works satisfactory well for the summer data, in winter interpretation is more difficult, which is attributed to either different vertical transport pathways or different chemical lifetimes in both seasons. The geographical distribution of the clusters together with histograms for nucleation and Aitken mode particles within each cluster are presented. Aitken mode particle number concentrations show a clear vertical gradient with the lowest values in the lowermost stratosphere (750–2820 particles/cm3 STP, minimum of the two 25% – and maximum of the two 75%-percentiles of both seasons) and the highest values for the boundary-layer-influenced air (4290–22 760 particles/cm3 STP). Nucleation mode particles are also highest in the boundary-layer-influenced air (1260–29 500 particles/cm3 STP), but are lowest in the free troposphere (0–450 particles/cm3 STP). The given submicrometer particle number concentrations represent the first large-scale seasonal data sets for the upper troposphere and lowermost stratosphere over the Eurasian continent.

scholarly journals River ice flux and water velocities along a 600 km-long reach of Lena River, Siberia, from satellite stereo

2013 ◽  
Vol 17 (11) ◽  
pp. 4671-4683 ◽  
Author(s):  
A. Kääb ◽  
M. Lamare ◽  
M. Abrams
Keyword(s):  
River Flow ◽  
Thermal Emission ◽  
Time Lag ◽  
Open Water ◽  
Image Resolution ◽  
Surface Velocity ◽  
River Ice ◽  
Data Set ◽  
Hazard Management ◽  
Lena River

Abstract. Knowledge of water-surface velocities in rivers is useful for understanding a range of river processes. In cold regions, river-ice break up and the related downstream transport of ice debris is often the most important hydrological event of the year, leading to flood levels that typically exceed those for the open-water period and to strong consequences for river infrastructure and ecology. Accurate and complete surface-velocity fields on rivers have rarely been produced. Here, we track river ice debris over a time period of about one minute, which is the typical time lag between the two or more images that form a stereo data set in spaceborne, along-track optical stereo mapping. Using a series of nine stereo scenes from the US/Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard the NASA Terra spacecraft with 15 m image resolution, we measure the ice and water velocity field over a 620 km-long reach of the lower Lena River, Siberia, just above its entry into the Lena delta. Careful analysis and correction of higher-order image and sensor errors enables an accuracy of ice-debris velocities of up to 0.04 m s−1 from the ASTER data. Maximum ice or water speeds, respectively, reach up to 2.5 m s−1 at the time of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear along-stream undulations with a wavelength of about 21 km that agree well with variations in channel width and with the location of sand bars along the river reach studied. The methodology and results of this study could be valuable to a number of disciplines requiring detailed information about river flow, such as hydraulics, hydrology, river ecology and natural-hazard management.

scholarly journals Initial MST radar observations of upper tropospheric-lower stratospheric duct-like structures over Jicamarca, Peru

2012 ◽  
Vol 12 (22) ◽  
pp. 11085-11093 ◽  
Author(s):  
Z. Li ◽  
S. Naqvi ◽  
A. J. Gerrard ◽  
J. L. Chau ◽  
Y. Bhattacharya
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Physical Nature ◽  
High Quality ◽  
Data Set ◽  
Upper Troposphere ◽  
Atmospheric Fronts ◽  
Mst Radar ◽  
Wind Measurements

Abstract. Persistent wind jet structures along zonal and meridional fields, believed to be caused by stationary gravity waves, were detected in February 1999 in mesosphere-stratosphere-troposphere (MST) radar wind measurements of the troposphere and lower stratosphere over Jicamarca, Peru. Over a continuous seven day span of MST-data analyzed in this study, two days of observations showed signatures of wave-like structures in the upper troposphere/lower stratosphere wind jets associated with the phases of the stationary gravity waves. We believe these wave-like structures are ducted gravity waves. We present these initial observations, their characteristics, and the results of simple numerical simulations used in an attempt to mimic these observed features. Although a fair replication of the observed ducted structure in the numerical model is found, the observed period of ~90 min is nonetheless much longer than what is traditionally observed. As a result, the specific physical nature of the observed structures is not fully established. Nevertheless, given the high quality of the observations, we demonstrate here that continued analysis of this data set and concurrent modeling efforts will allow for a better understanding of Doppler ducts at high spatial and temporal resolution, and the results presented here can ultimately be applied to studies of middle atmospheric fronts, ducts, and bores.

scholarly journals Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 balloon instrument

2007 ◽  
Vol 7 (6) ◽  
pp. 1599-1613 ◽  
Author(s):  
J. J. Remedios ◽  
G. Allen ◽  
A. M. Waterfall ◽  
H. Oelhaf ◽  
A. Kleinert ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Formic Acid ◽  
Organic Compounds ◽  
Thermal Emission ◽  
Emission Spectra ◽  
High Spectral Resolution ◽  
Spectral Features ◽  
Model Calculations ◽  
Upper Troposphere ◽  
Infra Red

Abstract. Organic compounds play a central role in troposphere chemistry and increasingly are a viable target for remote sensing observations. In this paper, infra-red spectral features of three organic compounds are investigated in thermal emission spectra recorded on a flight on 8 May 1998 near Aire sur l'Adour by a balloon-borne instrument, MIPAS-B2, operating at high spectral resolution. It is demonstrated, for the first time, that PAN and acetone can be detected in infra-red remote sensing spectra of the upper troposphere; detection results are presented at tangent altitudes of 10.4 km and 7.5 km (not acetone). In addition, the results provide the first observation of spectral features of formic acid in thermal emission, as opposed to solar occultation, and confirm that concentrations of this gas are measurable in the mid-latitude upper troposphere, given accurate spectroscopic data. For PAN, two bands are observed centred at 794 cm−1 and 1163 cm−1. For acetone and formic acid, one band has been detected for each so far with band centres at 1218 cm−1 and 1105 cm−1 respectively. Mixing ratios inferred at 10.4 km tangent altitude are 180 pptv and 530 pptv for PAN and acetone respectively, and 200 pptv for formic acid with HITRAN 2000 spectroscopy. Accuracies are on the order of 15 to 40%. The detection technique applied here is verified by examining weak but known signatures of CFC-12 and HCFC-22 in the same spectral regions as those of the organic compounds, with results confirming the quality of both the instrument and the radiative transfer model. The results suggest the possibility of global sensing of the organic compounds studied here which would be a major step forward in verifying and interpreting global tropospheric model calculations.

scholarly journals Global validation of improved SCIAMACHY scientific ozone limb data using ozonesonde measurements

2015 ◽  
Vol 8 (5) ◽  
pp. 4817-4858
Author(s):  
J. Jia ◽  
A. Rozanov ◽  
A. Ladstätter-Weißenmayer ◽  
J. P. Burrows
Keyword(s):  
Global Scale ◽  
Data Sets ◽  
Vertical Profiles ◽  
Data Set ◽  
Latitude Range ◽  
Ozone Profile ◽  
The Tropics ◽  
Relative Differences ◽  
Significant Underestimation ◽  
Good Agreement

Abstract. In this manuscript, the latest SCIAMACHY limb ozone scientific vertical profiles, namely the current V2.9 and the upcoming V3.0, are extensively compared with ozone sonde data from the WOUDC database. The comparisons are made on a global scale from 2003 to 2011, involving 61 sonde stations. The retrieval processors used to generate V2.9 and V3.0 data sets are briefly introduced. The comparisons are discussed in terms of vertical profiles and stratospheric partial columns. Our results indicate that the V2.9 ozone profile data between 20–30 km is in good agreement with ground based measurements with less than 5% relative differences in the latitude range of 90° S–40° N (with exception of the tropical Pacific region where an overestimation of more than 10% is observed), which corresponds to less than 5 DU partial column differences. In the tropics the differences are within 3%. However, this data set shows a significant underestimation northwards of 40° N (up to ~15%). The newly developed V3.0 data set reduces this bias to below 10% while maintaining a good agreement southwards of 40° N with slightly increased relative differences of up to 5% in the tropics.

Sign in / Sign up

Export Citation Format

Share Document