scholarly journals HDO/H<sub>2</sub>O ratio retrievals from GOSAT

2012 ◽  
Vol 5 (5) ◽  
pp. 6643-6677 ◽  
Author(s):  
H. Boesch ◽  
N. M. Deutscher ◽  
T. Warneke ◽  
K. Byckling ◽  
A. J. Cogan ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
A Priori ◽  
Regional Scale ◽  
Atmospheric Temperature ◽  
Total Carbon ◽  
Latitudinal Gradients ◽  
Random Errors ◽  
Synthetic Simulation ◽  
Shortwave Infrared

Abstract. We report a new shortwave infrared (SWIR) retrieval of the column-averaged HDO/H2O ratio from the Japanese Greenhouse Gases Observing SATellite (GOSAT). From synthetic simulation studies, we have estimated that the inferred δD values will typically have random errors between 20‰ (desert surface and 30° solar zenith angle) and 120‰ (conifer surface and 60° solar zenith angle). We find that the retrieval will have a small, but significant sensitivity to the presence of cirrus clouds, the HDO a priori profile shape and atmospheric temperature, which has the potential for introducing some regional-scale biases in the retrieval. From comparisons to ground-based column observations from the Total Carbon Column Observing Network (TCCON) we find differences between δD from GOSAT and TCCON of around −30‰ for northern-hemispheric sites which increase up to −70‰ for Australian sites. The bias for the Australian sites significantly reduces when decreasing the spatial co-location criteria, which shows that spatial averaging contributes to the observed differences over Australia. The GOSAT retrievals allow mapping the global distribution of δD and its variations with season and we find in our global GOSAT retrievals the expected strong latitudinal gradients with significant enhancements over the tropics. The comparisons to the ground-based TCCON network and the results of the global retrieval are very encouraging and they show that δD retrieved from GOSAT should be a useful product that can be used to complement datasets from thermal-infrared sounder and ground-based networks and to extend the δD dataset from SWIR retrievals established from the recently ended SCIAMACHY mission.

scholarly journals HDO/H<sub>2</sub>O ratio retrievals from GOSAT

2013 ◽  
Vol 6 (3) ◽  
pp. 599-612 ◽  
Author(s):  
H. Boesch ◽  
N. M. Deutscher ◽  
T. Warneke ◽  
K. Byckling ◽  
A. J. Cogan ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
A Priori ◽  
Regional Scale ◽  
Atmospheric Temperature ◽  
Total Carbon ◽  
Latitudinal Gradients ◽  
Random Errors ◽  
Synthetic Simulation ◽  
Shortwave Infrared

Abstract. We report a new shortwave infrared (SWIR) retrieval of the column-averaged HDO/H2O ratio from the Japanese Greenhouse Gases Observing Satellite (GOSAT). From synthetic simulation studies, we have estimated that the inferred δD values will typically have random errors between 20‰ (desert surface and 30° solar zenith angle) and 120‰ (conifer surface and 60° solar zenith angle). We find that the retrieval will have a small but significant sensitivity to the presence of cirrus clouds, the HDO a priori profile shape and atmospheric temperature, which has the potential of introducing some regional-scale biases in the retrieval. From comparisons to ground-based column observations from the Total Carbon Column Observing Network (TCCON), we find differences between δD from GOSAT and TCCON of around −30‰ for northern hemispheric sites which increase up to −70‰ for Australian sites. The bias for the Australian sites significantly reduces when decreasing the spatial co-location criteria, which shows that spatial averaging contributes to the observed differences over Australia. The GOSAT retrievals allow mapping the global distribution of δD and its variations with season, and we find in our global GOSAT retrievals the expected strong latitudinal gradients with significant enhancements over the tropics. The comparisons to the ground-based TCCON network and the results of the global retrieval are very encouraging, and they show that δD retrieved from GOSAT should be a useful product that can be used to complement datasets from thermal-infrared sounder and ground-based networks and to extend the δD dataset from SWIR retrievals established from the recently ended SCIAMACHY mission.

scholarly journals Using self organising maps to explore ozone profile validation results – SCIAMACHY limb compared to ground-based lidar observations

2014 ◽  
Vol 7 (4) ◽  
pp. 4373-4406
Author(s):  
J. A. E. van Gijsel ◽  
R. Zurita-Milla ◽  
P. Stammes ◽  
S. Godin-Beekmann ◽  
T. Leblanc ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
A Priori ◽  
Relative Difference ◽  
Full Time ◽  
Self Organizing Map ◽  
Ozone Profile ◽  
The Difference ◽  
Ground Based Lidar ◽  
Lidar Observations

Abstract. Traditional validation of atmospheric profiles is based on the intercomparison of two or more datasets in predefined ranges or classes of a given observational characteristic such as latitude or solar zenith angle. In this study we train a self organizing map (SOM) with a full time series of relative difference profiles of SCIAMACHY limb v5.02 and lidar ozone profiles from seven observation sites. Each individual observation characteristic is then mapped to the obtained SOM to investigate to which degree variation in this characteristic is explanatory for the variation seen in the SOM map. For the studied datasets, altitude-dependent relations for the global dataset were found between the difference profiles and studied variables. From the lowest altitude studied (18 km) ascending, the most influencing factors were found to be longitude, followed by solar zenith angle and latitude, sensor age and again solar zenith angle together with the day of the year at the highest altitudes studied here (up to 45 km). Clustering into three classes showed that there are also some local dependencies, with for instance one cluster having a much stronger correlation with the sensor age (days since launch) between 36 and 42 km. It was shown that the proposed approach provides a powerful tool for the exploring of differences between datasets without being limited to a-priori defined data subsets.

scholarly journals Using self-organising maps to explore ozone profile validation results – SCIAMACHY limb compared to ground-based lidar observations

2015 ◽  
Vol 8 (5) ◽  
pp. 1951-1963
Author(s):  
J. A. E. van Gijsel ◽  
R. Zurita-Milla ◽  
P. Stammes ◽  
S. Godin-Beekmann ◽  
T. Leblanc ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
A Priori ◽  
Relative Difference ◽  
Data Sets ◽  
Full Time ◽  
Data Set ◽  
Partial Correlations ◽  
The Difference ◽  
Ground Based Lidar

Abstract. Traditional validation of atmospheric profiles is based on the intercomparison of two or more data sets in predefined ranges or classes of a given observational characteristic such as latitude or solar zenith angle. In this study we trained a self-organising map (SOM) with a full time series of relative difference profiles of SCIAMACHY limb v5.02 and lidar ozone profiles from seven observation sites. Each individual observation characteristic was then mapped to the obtained SOM to investigate to which degree variation in this characteristic is explanatory for the variation seen in the SOM map. For the studied data sets, altitude-dependent relations for the global data set were found between the difference profiles and studied variables. From the lowest altitude studied (18 km) ascending, the most influencing factors were found to be longitude, followed by solar zenith angle and latitude, sensor age and again solar zenith angle together with the day of the year at the highest altitudes studied here (up to 45 km). After accounting for both latitude and longitude, residual partial correlations with a reduced magnitude are seen for various factors. However, (partial) correlations cannot point out which (combination) of the factors drives the observed differences between the ground-based and satellite ozone profiles as most of the factors are inter-related. Clustering into three classes showed that there are also some local dependencies, with for instance one cluster having a much stronger correlation with the sensor age (days since launch) between 36 and 42 km. The proposed SOM-based approach provides a powerful tool for the exploration of differences between data sets without being limited to a priori defined data subsets.

Effect of solar zenith angle on satellite cloud retrievals based on O2–O2 absorption band

2021 ◽  
Vol 42 (11) ◽  
pp. 4224-4240
Author(s):  
Gyuyeon Kim ◽  
Yong-Sang Choi ◽  
Sang Seo Park ◽  
Jhoon Kim
Keyword(s):  
Absorption Band ◽  
Zenith Angle ◽  
Solar Zenith Angle

Sun-induced production of vitamin D3 throughout 1 year in tropical and subtropical regions: relationship with latitude, cloudiness, UV-B exposure and solar zenith angle

2021 ◽  
Vol 20 (2) ◽  
pp. 265-274
Author(s):  
Angela C. G. B. Leal ◽  
Marcelo P. Corrêa ◽  
Michael F. Holick ◽  
Enaldo V. Melo ◽  
Marise Lazaretti-Castro
Keyword(s):  
Zenith Angle ◽  
Vitamin D3 ◽  
Solar Zenith Angle

scholarly journals Effects of Diurnal Variations on Tropical Equilibrium States: A Two-Dimensional Cloud-Resolving Modeling Study

2007 ◽  
Vol 64 (2) ◽  
pp. 656-664 ◽  
Author(s):  
Shouting Gao ◽  
Yushu Zhou ◽  
Xiaofan Li
Keyword(s):  
Equilibrium State ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Diurnal Variations ◽  
Equilibrium States ◽  
Sea Surface ◽  
Two Dimensional ◽  
Time Invariant

Abstract Effects of diurnal variations on tropical heat and water vapor equilibrium states are investigated based on hourly data from two-dimensional cloud-resolving simulations. The model is integrated for 40 days and the simulations reach equilibrium states in all experiments. The simulation with a time-invariant solar zenith angle produces a colder and drier equilibrium state than does the simulation with a diurnally varied solar zenith angle. The simulation with a diurnally varied sea surface temperature generates a colder equilibrium state than does the simulation with a time-invariant sea surface temperature. Mass-weighted mean temperature and precipitable water budgets are analyzed to explain the thermodynamic differences. The simulation with the time-invariant solar zenith angle produces less solar heating, more condensation, and consumes more moisture than the simulation with the diurnally varied solar zenith angle. The simulation with the diurnally varied sea surface temperature produces a colder temperature through less latent heating and more IR cooling than the simulation with the time-invariant sea surface temperature.

Sign in / Sign up

Export Citation Format

Share Document