scholarly journals Evaluation of the hydrological cycle of MATCH driven by NCEP reanalysis data: comparison with GOME water vapor measurements

2005 ◽  
Vol 5 (4) ◽  
pp. 887-908 ◽  
Author(s):  
R. Lang ◽  
M. G. Lawrence
Keyword(s):  
Water Vapor ◽  
Regional Differences ◽  
Hydrological Cycle ◽  
Transport Model ◽  
Global Precipitation Climatology Project ◽  
Global Scale ◽  
Reanalysis Data ◽  
Model Parameters ◽  
Ncep Reanalysis ◽  
Inter Tropical Convergence Zone

Abstract. This study examines two key parameters of the hydrological cycle, water vapor (WV) and precipitation rates (PR), as modelled by the chemistry transport model MATCH (Model of Atmospheric Transport and Chemistry) driven by National Centers for Environmental Prediction (NCEP) reanalysis data (NRA). For model output evaluation we primarily employ WV total column data from the Global Ozone Monitoring Experiment (GOME) on ERS-2, which is the only instrument capable measuring WV on a global scale and over all surface types with a substantial data record from 1995 to the present. We find that MATCH and NRA WV and PR distributions are closely related, but that significant regional differences in both parameters exist in magnitude and distribution patterns when compared to the observations. We also find that WV residual patterns between model and observations show remarkable similarities to residuals observed in the PR when comparing MATCH and NRA output to observations comprised by the Global Precipitation Climatology Project (GPCP). We conclude that deficiencies in model parameters shared by MATCH and NRA, like in the surface evaporation rates and regional transport patterns, are likely to lead to the observed differences. Monthly average regional differences between MATCH modelled WV columns and the observations can be as large as 2 cm, based on the analysis of three years. Differences in the global mean WV values are, however, below 0.1 cm. Regional differences in the PR between MATCH and GPCP can be above 0.5 cm per day and MATCH computes on average a higher PR than what has been observed. The lower water vapor content of MATCH is related to shorter model WV residence times by up to 1 day as compared to the observations. We find that MATCH has problems in modelling the WV content in regions of strong upward convection like, for example, along the Inter Tropical Convergence Zone, where it appears to be generally too dry as compared to the observations. We discuss possible causes for this bias and demonstrate the value of the GOME WV record for model evaluation.

scholarly journals Evaluation of the hydrological cycle of MATCH driven by NCEP reanalysis data: comparison with GOME water vapor field measurements

2004 ◽  
Vol 4 (6) ◽  
pp. 7917-7984 ◽  
Author(s):  
R. Lang ◽  
M. G. Lawrence
Keyword(s):  
Water Vapor ◽  
Regional Differences ◽  
Hydrological Cycle ◽  
Transport Model ◽  
Global Precipitation Climatology Project ◽  
Reanalysis Data ◽  
Model Parameters ◽  
Residence Times ◽  
Ncep Reanalysis ◽  
Inter Tropical Convergence Zone

Abstract. This study examines two key parameters of the hydrological cycle, water vapor (WV) and precipitation rates (PR), as modelled by the chemistry transport model MATCH (Model of Atmospheric Transport and Chemistry) driven by National Centers for Environmental Prediction (NCEP) reanalysis data (NRA). For model output evaluation we employ WV total column data from the Global Ozone Monitoring Experiment (GOME) on ERS-2, which is the only instrument capable measuring WV on a global scale and over all surface types with a substantial data record from 1995 to the present. We find that MATCH and NRA WV and PR distributions are closely related, but that significant regional differences in both parameters exist in magnitude and distribution patterns when compared to the observations. We also find that WV residual patterns between model and observations show remarkable similarities to residuals observed in the PR when comparing MATCH and NRA output to observations comprised by the Global Precipitation Climatology Project (GPCP). We conclude that deficiencies in model parameters shared by MATCH and NRA, like, for example, in the evapotranspiration rates, are likely to lead to the observed differences. Regional differences between MATCH modelled WV columns and the observations can be as large as 2 cm on the basis of a three years monthly average. Differences in the global mean WV values are, however, below 1 mm. Regional differences in the PR between MATCH and GPCP can be above 5 mm per day and MATCH computes on average a higher PR than what has been observed. As a consequence, this leads to shorter model WV residence times by about 1 day as compared to NRA data and the observations. We find that MATCH has problems in modelling the WV content in regions of strong upward convection like, for example, along the Inter Tropical Convergence Zone, where it appears to be generally too dry as compared to the observations. The study therefore suggests that a too rapid conversion of WV to precipitate in MATCH, especially in instances of strong convection, leads to regionally too dry model results and in turn to generally too low WV residence times. The study additionally demonstrates the value of the GOME WV record for model evaluation.

scholarly journals Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra

2013 ◽  
Vol 6 (2) ◽  
pp. 263-274 ◽  
Author(s):  
C. Frankenberg ◽  
D. Wunch ◽  
G. Toon ◽  
C. Risi ◽  
R. Scheepmaker ◽  
...  
Keyword(s):  
Water Vapor ◽  
Hydrological Cycle ◽  
Time Frame ◽  
Global Scale ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Validation Dataset ◽  
Spatial Correlations ◽  
Vertical Column ◽  
Shortwave Infrared

Abstract. Remote sensing of the isotopic composition of water vapor can provide valuable information on the hydrological cycle. Here, we demonstrate the feasibility of retrievals of the relative abundance of HDO (the HDO/H2O ratio) from the Japanese GOSAT satellite. For this purpose, we use high spectral resolution nadir radiances around 6400 cm−1 (1.56 μm) to retrieve vertical column amounts of H2O and HDO. Retrievals of H2O correlate well with ECMWF (European Centre for Medium-Range Weather Forecasts) integrated profiles (r2 = 0.96). Typical precision errors in the retrieved column-averaged deuterium depletion (δD) are 20–40‰. We compare δD against a TCCON (Total Carbon Column Observing Network) ground-based station in Lamont, Oklahoma. Using retrievals in very dry areas over Antarctica, we detect a small systematic offset in retrieved H2O and HDO column amounts and take this into account for a bias correction of δD. Monthly averages of δD in the June 2009 to September 2011 time frame are well correlated with TCCON (r2 = 0.79) and exhibit a slope of 0.98 (1.23 if not bias corrected). We also compare seasonal averages on the global scale with results from the SCIAMACHY instrument in the 2003–2005 time frame. Despite the lack of temporal overlap, seasonal averages in general agree well, with spatial correlations (r2) ranging from 0.62 in September through November to 0.83 in June through August. However, we observe higher variability in GOSAT δD, indicated by fitted slopes between 1.2 and 1.46. The discrepancies are likely related to differences in vertical sensitivities but warrant further validation of both GOSAT and SCIAMACHY and an extension of the validation dataset.

scholarly journals Hydrological controls on the tropospheric ozone greenhouse gas effect

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Le Kuai ◽  
Kevin W. Bowman ◽  
Helen M. Worden ◽  
Robert L. Herman ◽  
Susan S. Kulawik
Keyword(s):  
Water Vapor ◽  
Greenhouse Gas ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Hydrological Cycle ◽  
Longwave Radiation ◽  
Hadley Cell ◽  
Water Vapor Absorption ◽  
Inter Tropical Convergence Zone ◽  
Tropospheric O3

The influence of the hydrological cycle in the greenhouse gas (GHG) effect of tropospheric ozone (O3) is quantified in terms of the O3 longwave radiative effect (LWRE), which is defined as the net reduction of top-of-atmosphere flux due to total tropospheric O3 absorption. The O3 LWRE derived from the infrared spectral measurements by Aura’s Tropospheric Emission Spectrometer (TES) show that the spatiotemporal variation of LWRE is relevant to relative humidity, surface temperature, and tropospheric O3 column. The zonally averaged subtropical LWRE is ~0.2 W m–2 higher than the zonally averaged tropical LWRE, generally due to lower water vapor concentrations and less cloud coverage at the downward branch of the Hadley cell in the subtropics. The largest values of O3 LWRE over the Middle East (>1 W/m2) are further due to large thermal contrasts and tropospheric ozone enhancements from atmospheric circulation and pollution. Conversely, the low O3 LWRE over the Inter-Tropical Convergence Zone (on average 0.4 W m–2) is due to strong water vapor absorption and cloudiness, both of which reduce the tropospheric O3 absorption in the longwave radiation. These results show that changes in the hydrological cycle due to climate change could affect the magnitude and distribution of ozone radiative forcing.

Diagnosis of Subtropical Humidity Dynamics Using Tracers of Last Saturation

2005 ◽  
Vol 62 (9) ◽  
pp. 3353-3367 ◽  
Author(s):  
Joseph Galewsky ◽  
Adam Sobel ◽  
Isaac Held
Keyword(s):  
Water Vapor ◽  
General Circulation ◽  
Large Scale ◽  
Transport Model ◽  
Thermal Relaxation ◽  
Circulation Model ◽  
Reanalysis Data ◽  
Tracer Transport ◽  
Dry Air ◽  
Model Match

Abstract A technique for diagnosing the mechanisms that control the humidity in a general circulation model (GCM) or observationally derived meteorological analysis dataset is presented. The technique involves defining a large number of tracers, each of which represents air that has last been saturated in a particular region of the atmosphere. The time-mean tracer fields show the typical pathways that air parcels take between one occurrence of saturation and the next. The tracers provide useful information about how different regions of the atmosphere influence the humidity elsewhere. Because saturation vapor pressure is a function only of temperature and assuming mixing ratio is conserved for unsaturated parcels, these tracer fields can also be used together with the temperature field to reconstruct the water vapor field. The technique is first applied to an idealized GCM in which the dynamics are dry and forced using the Held–Suarez thermal relaxation, but the model carries a passive waterlike tracer that is emitted at the surface and lost due to large-scale condensation with zero latent heat release and no condensate retained. The technique provides an accurate reconstruction of the simulated water vapor field. In this model, the dry air in the subtropical troposphere is produced primarily by isentropic transport and is moistened somewhat by mixing with air from lower levels, which has not been saturated since last contact with the surface. The technique is then applied to the NCEP–NCAR reanalysis data from December–February (DJF) 2001/02, using the offline tracer transport model MATCH. The results show that the dryness of the subtropical troposphere is primarily controlled by isentropic transport of very dry air by midlatitude eddies and that diabatic descent from the tropical upper troposphere plays a secondary role in controlling the dryness of the subtropics.

scholarly journals C-GEM (v 1.0): a new, cost-efficient biogeochemical model for estuaries and its application to a funnel-shaped system

2013 ◽  
Vol 6 (4) ◽  
pp. 5645-5709 ◽  
Author(s):  
C. Volta ◽  
S. Arndt ◽  
H. H. G. Savenije ◽  
G. G. Laruelle ◽  
P. Regnier
Keyword(s):  
Reactive Transport ◽  
Model Comparison ◽  
Transport Model ◽  
Current Model ◽  
Global Scale ◽  
Salt Transport ◽  
Biogeochemical Model ◽  
Model Parameters ◽  
Estuarine System ◽  
Computationally Efficient

Abstract. The first part of this paper describes C-GEM (Carbon – Generic Estuary Model), a new, one-dimensional, generic reactive-transport model for the biogeochemical dynamics of carbon and associated bio-elements (N, P, Si) in estuaries. C-GEM is computationally efficient and reduces data-requirements by using an idealized representation of the estuarine geometry to quantitatively predict the dominant features of the estuarine hydrodynamics, salt transport and biogeochemistry. A protocol for the set-up of C-GEM for an estuarine system is also described. The second part of this paper presents, as a proof of concept, the application of C-GEM to the funnel-shaped Scheldt estuary (Belgium, the Netherlands), one of the best-surveyed system in the world. Steady-state and transient simulations are performed and the performance of C-GEM is evaluated through model-data and model-model comparison, using integrated measures of the estuarine biogeochemical functioning, such as system-wide estimates of the Net Ecosystem Metabolism (NEM). A sensitivity analysis is also carried out to identify model parameters that exert the most important control on biogeochemical processes and to assess the sensitivity of the NEM to uncertainties in parameter values. The paper ends by a short discussion of current model limitations with respect to local, regional and global scale applications.

scholarly journals Interannual variability in hindcasts of atmospheric chemistry: the role of meteorology

2009 ◽  
Vol 9 (14) ◽  
pp. 5261-5280 ◽  
Author(s):  
P. Hess ◽  
N. Mahowald
Keyword(s):  
Water Vapor ◽  
Surface Temperature ◽  
Interannual Variability ◽  
Atmospheric Chemistry ◽  
El Niño ◽  
Hydrological Cycle ◽  
Transport Model ◽  
El Nino ◽  
Climate Simulation ◽  
Relative Variability

Abstract. Two 40-year meteorological datasets are used to drive the Model of Ozone and Related Tracers chemical transport model, version 2 (MOZART2) in hindcast simulations. One dataset is from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis, the second dataset uses meteorology from the Community Atmosphere Model (CAM3) forced with observed interannually varying sea surface temperatures. All emissions, except those from lightning are annually constant. Analysis of these simulations focuses on the period between 1979–1999, due to meteorological discontinuities in the NCEP reanalysis during the 1970s. The meteorology using CAM3 captures observed trends in temperature and water vapor; the simulation using NCEP meteorology does not. This paper examines the regional and global interannual variability of various chemical and meteorological fields: CO, OH, O3 and HNO3, the surface photolysis rate of NO2 (as a proxy for overhead cloudiness), lightning NO emissions, water vapor, planetary boundary layer height, and temperature. The variability due to changes in emissions is not considered in this analysis. In both the NCEP and CAM3 simulations the relative variability of CO, OH, O3 and HNO3 are qualitatively similar, with variability maxima both in the tropics and the high latitudes. Locally, relative variability generally ranges between 3 and 10%; globally the tropospheric variability generally ranges from half to one percent, but can be higher. For most fields the leading global Empirical Orthogonal Function explains approximately 10% of the variability and correlates significantly with El Niño. In both simulations the first principal component of a multiple tracer, globally averaged analysis shows a strong coupling between surface temperature, measures of the hydrological cycle, CO and OH, but is not correlated with El Niño. In both simulations we examine the global response of the selected variables to changes in global surface temperature, and compare with a climate simulation over the 21st century.

scholarly journals Interannual variability in hindcasts of atmospheric chemistry: the role of meteorology

2009 ◽  
Vol 9 (1) ◽  
pp. 3485-3534
Author(s):  
P. Hess ◽  
N. Mahowald
Keyword(s):  
Water Vapor ◽  
Surface Temperature ◽  
Interannual Variability ◽  
Atmospheric Chemistry ◽  
El Niño ◽  
Hydrological Cycle ◽  
Transport Model ◽  
El Nino ◽  
Climate Simulation ◽  
Relative Variability

Abstract. Two 40-year meteorological datasets are used to drive the Model of Ozone and Related Tracers chemical transport model, version 2 (MOZART2) in hindcast simulations. One dataset is from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis, the second dataset uses meteorology from the Community Atmosphere Model (CAM3) forced with observed interannually varying sea surface temperatures. All emissions, except those from lightning are annually constant. Analysis of these simulations is from 1979–1999, due to meteorological discontinuities in the NCEP reanalysis during the 1970s. The meteorology using CAM3 captures observed trends in temperature, water vapor, precipitation and cloudiness; the simulation using NCEP meteorology does not. This paper examines the regional and global interannual variability of various chemical and meteorological fields: CO, OH, O3 and HNO3, the surface photolysis rate of NO2 (as a proxy for overhead cloudiness), lightning NO emissions, water vapor, planetary boundary layer height, and temperature. The variability due to changes in emissions is not considered in this analysis. In both the NCEP and CAM3 simulations the relative variability of CO, OH, O3 and HNO3 are qualitatively similar, with variability maxima both in the tropics and the high latitudes. Locally, relative variability generally ranges between 3 and 10%; globally the tropospheric variability generally ranges from half to one percent, but can be higher. For most fields the leading Empirical Orthogonal Function explains approximately 10% of the variability and correlates significantly with El Niño. In both simulations the first principal component of a multiple tracer, globally averaged analysis shows a strong coupling between surface temperature, measures of the hydrological cycle, CO and OH, but is not correlated with El Niño. In both simulations we examine the global response of the selected variables to changes in global surface temperature, and compare with a climate simulation over the 21st century.

scholarly journals Stochastic Analysis of Hourly to Monthly Potential Evapotranspiration with a Focus on the Long-Range Dependence and Application with Reanalysis and Ground-Station Data

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 177
Author(s):  
Panayiotis Dimitriadis ◽  
Aristoteles Tegos ◽  
Demetris Koutsoyiannis
Keyword(s):  
Long Range ◽  
Hydrological Cycle ◽  
Potential Evapotranspiration ◽  
Global Scale ◽  
Reanalysis Data ◽  
Shortwave Radiation ◽  
Long Range Dependence ◽  
Dependence Structure ◽  
Ground Station ◽  
Cycle Path

The stochastic structures of potential evaporation and evapotranspiration (PEV and PET or ETo) are analyzed using the ERA5 hourly reanalysis data and the Penman–Monteith model applied to the well-known CIMIS network. The latter includes high-quality ground meteorological samples with long lengths and simultaneous measurements of monthly incoming shortwave radiation, temperature, relative humidity, and wind speed. It is found that both the PEV and PET processes exhibit a moderate long-range dependence structure with a Hurst parameter of 0.64 and 0.69, respectively. Additionally, it is noted that their marginal structures are found to be light-tailed when estimated through the Pareto–Burr–Feller distribution function. Both results are consistent with the global-scale hydrological-cycle path, determined by all the above variables and rainfall, in terms of the marginal and dependence structures. Finally, it is discussed how the existence of, even moderate, long-range dependence can increase the variability and uncertainty of both processes and, thus, limit their predictability.

scholarly journals COMPARISON OF GNSS PWV AND ERA5-DERIVED PWV BASED ON GNSS PWV IN HONG KONG, CHINA

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 987-993
Author(s):  
Z. W. Li ◽  
C. Z. Tang ◽  
S. H. Tang ◽  
Y. Zhang
Keyword(s):  
Hong Kong ◽  
Water Vapor ◽  
Hydrological Cycle ◽  
Precipitable Water ◽  
Weather Forecast ◽  
Reanalysis Data ◽  
Vital Role ◽  
Small Range ◽  
Data Set ◽  
Medium Range Weather Forecast

Abstract. Water vapor is the most abundant atmospheric gas, and it plays a vital role in the evolution of the Earth's climate. Precipitable water vapor (PWV) is a key factor in monitoring the climate and hydrological cycle. The use of GNSS to estimate PWV is a very effective method. This paper uses 17 satellite positioning reference stations in SatRef, Hong Kong, China, in 2017 to calculate the PWV and introduce the latest reanalysis data set of the European Medium Range Weather Forecast Ingenued Center (ECMWF) ERA5 into this study. The accuracy of THE PWV derived from ERA5 was evaluated using the GNSS-derived PWV. In Hong Kong, the annual bias and RMSE values of GNSS-derived ZTD and ERA5-derived ZTDs are 1.16 cm and 1.78 cm respectively, while the annual RMSE values of GNSS-derived PWV and ERA5-derived PWV are 0.51 cm and 0.57 cm, respectively. The daily changes of GNSS PWV in 2017 are analyzed, and the results show that the ZTD effect of THE ERA5 reanalysis data derived in the small range area is not very ideal, but the accuracy of the PWV derived from ERA5 is better.

scholarly journals Water vapor isotopologues retrievals from high resolution GOSAT short-wave infrared spectra

2012 ◽  
Vol 5 (5) ◽  
pp. 6357-6386 ◽  
Author(s):  
C. Frankenberg ◽  
D. Wunch ◽  
G. Toon ◽  
C. Risi ◽  
R. Scheepmaker ◽  
...  
Keyword(s):  
Water Vapor ◽  
Hydrological Cycle ◽  
Time Frame ◽  
Short Wave ◽  
Global Scale ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Validation Dataset ◽  
Spatial Correlations ◽  
Vertical Column

Abstract. Remote sensing of the isotopic composition of water vapor can provide valuable information on the hydrological cycle. Here, we demonstrate feasibility of retrievals of the relative abundance of HDO (the HDO/H2O ratio) from the Japanese GOSAT satellite. For this purpose, we use high spectral resolution nadir radiances around 6400 cm−1 (1.56 μm) to retrieve vertical column amounts of H2O and HDO. Retrievals of H2O correlate well with ECMWF (European Centre for Medium-Range Weather Forecasts) integrated profiles (r2 = 0.96). Typical precision errors in the retrieved column averaged deuterium depletion (δD) are 20–40‰. We validate δD against a TCCON (Total Carbon Column Observing Network) ground-based station in Lamont, Oklahoma. Using retrievals in very dry areas over Antarctica, we detect a small systematic offset in retrieved H2O and HDO column amounts and take this into account for a bias-correction of δD. Monthly averages of δD in the June 2009 to September 2011 time-frame are well correlated with TCCON (r2 = 0.79) and exhibit a slope of 0.98 (1.23 if not bias corrected). We also compare seasonal averages on the global scale with results from the SCIAMACHY instrument in the 2003–2005 timeframe. Despite the lack of temporal overlap, seasonal averages in general agree well, with spatial correlations (r2) ranging from 0.62 in September through November to 0.83 in June through August. However, we observe higher variability in GOSAT δD, indicated by fitted slopes between 1.2 and 1.46. The discrepancies are likely related to differences in vertical sensitivities but warrant further validation of both GOSAT and SCIAMACHY and an extension of the validation dataset.

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