Lower Stratospheric Water Vapor Variations Diagnosed from Satellite Observations, Reanalysis Data, and a Chemistry—Climate Model

2021 ◽  
Vol 35 (4) ◽  
pp. 701-715
Author(s):  
Yan Xia ◽  
Yi Huang ◽  
Yongyun Hu ◽  
Jun Yang
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
Reanalysis Data ◽  
Satellite Observations ◽  
Stratospheric Water Vapor

scholarly journals Assessment of upper tropospheric and stratospheric water vapor and ozone in reanalyses as part of S-RIP

2017 ◽  
Vol 17 (20) ◽  
pp. 12743-12778 ◽  
Author(s):  
Sean M. Davis ◽  
Michaela I. Hegglin ◽  
Masatomo Fujiwara ◽  
Rossana Dragani ◽  
Yayoi Harada ◽  
...  
Keyword(s):  
Water Vapor ◽  
Vertical Distribution ◽  
Climate Model ◽  
Reanalysis Data ◽  
Future Research ◽  
Total Column Ozone ◽  
Stratospheric Water Vapor ◽  
Tropical Tropopause ◽  
Weak Constraints ◽  
The Vertical Distribution

Abstract. Reanalysis data sets are widely used to understand atmospheric processes and past variability, and are often used to stand in as "observations" for comparisons with climate model output. Because of the central role of water vapor (WV) and ozone (O3) in climate change, it is important to understand how accurately and consistently these species are represented in existing global reanalyses. In this paper, we present the results of WV and O3 intercomparisons that have been performed as part of the SPARC (Stratosphere–troposphere Processes and their Role in Climate) Reanalysis Intercomparison Project (S-RIP). The comparisons cover a range of timescales and evaluate both inter-reanalysis and observation-reanalysis differences. We also provide a systematic documentation of the treatment of WV and O3 in current reanalyses to aid future research and guide the interpretation of differences amongst reanalysis fields.The assimilation of total column ozone (TCO) observations in newer reanalyses results in realistic representations of TCO in reanalyses except when data coverage is lacking, such as during polar night. The vertical distribution of ozone is also relatively well represented in the stratosphere in reanalyses, particularly given the relatively weak constraints on ozone vertical structure provided by most assimilated observations and the simplistic representations of ozone photochemical processes in most of the reanalysis forecast models. However, significant biases in the vertical distribution of ozone are found in the upper troposphere and lower stratosphere in all reanalyses.In contrast to O3, reanalysis estimates of stratospheric WV are not directly constrained by assimilated data. Observations of atmospheric humidity are typically used only in the troposphere, below a specified vertical level at or near the tropopause. The fidelity of reanalysis stratospheric WV products is therefore mainly dependent on the reanalyses' representation of the physical drivers that influence stratospheric WV, such as temperatures in the tropical tropopause layer, methane oxidation, and the stratospheric overturning circulation. The lack of assimilated observations and known deficiencies in the representation of stratospheric transport in reanalyses result in much poorer agreement amongst observational and reanalysis estimates of stratospheric WV. Hence, stratospheric WV products from the current generation of reanalyses should generally not be used in scientific studies.

scholarly journals Impacts of Ozone Changes in the Tropopause Layer on Stratospheric Water Vapor

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 291
Author(s):  
Jinpeng Lu ◽  
Fei Xie ◽  
Hongying Tian ◽  
Jiali Luo
Keyword(s):  
Water Vapor ◽  
Ozone Depletion ◽  
Climate Model ◽  
Global Climate ◽  
Stratospheric Water Vapor ◽  
Radiative Processes ◽  
Low Latitudes ◽  
Cold Point ◽  
The Impact ◽  
Tropopause Temperature

Stratospheric water vapor (SWV) changes play an important role in regulating global climate change, and its variations are controlled by tropopause temperature. This study estimates the impacts of tropopause layer ozone changes on tropopause temperature by radiative process and further influences on lower stratospheric water vapor (LSWV) using the Whole Atmosphere Community Climate Model (WACCM4). It is found that a 10% depletion in global (mid-low and polar latitudes) tropopause layer ozone causes a significant cooling of the tropical cold-point tropopause with a maximum cooling of 0.3 K, and a corresponding reduction in LSWV with a maximum value of 0.06 ppmv. The depletion of tropopause layer ozone at mid-low latitudes results in cooling of the tropical cold-point tropopause by radiative processes and a corresponding LSWV reduction. However, the effect of polar tropopause layer ozone depletion on tropical cold-point tropopause temperature and LSWV is opposite to and weaker than the effect of tropopause layer ozone depletion at mid-low latitudes. Finally, the joint effect of tropopause layer ozone depletion (at mid-low and polar latitudes) causes a negative cold-point tropopause temperature and a decreased tropical LSWV. Conversely, the impact of a 10% increase in global tropopause layer ozone on LSWV is exactly the opposite of the impact of ozone depletion. After 2000, tropopause layer ozone decreased at mid-low latitudes and increased at high latitudes. These tropopause layer ozone changes at different latitudes cause joint cooling in the tropical cold-point tropopause and a reduction in LSWV. Clarifying the impacts of tropopause layer ozone changes on LSWV clearly is important for understanding and predicting SWV changes in the context of future global ozone recovery.

scholarly journals Effect of the Indo-Pacific Warm Pool on Lower-Stratospheric Water Vapor and Comparison with the Effect of ENSO

2018 ◽  
Vol 31 (3) ◽  
pp. 929-943 ◽  
Author(s):  
Fei Xie ◽  
Xin Zhou ◽  
Jianping Li ◽  
Quanliang Chen ◽  
Jiankai Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Warm Pool ◽  
Latent Heat Release ◽  
Stratospheric Water Vapor ◽  
Asymmetric Effects ◽  
Pacific Warm Pool ◽  
Tropopause Temperature

Abstract Time-slice experiments with the Whole Atmosphere Community Climate Model, version 4 (WACCM4), and composite analysis with satellite observations are used to demonstrate that the Indo-Pacific warm pool (IPWP) can significantly affect lower-stratospheric water vapor. It is found that a warmer IPWP significantly dries the stratospheric water vapor by causing a broad cooling of the tropopause, and vice versa for a colder IPWP. Such imprints in tropopause temperature are driven by a combination of variations in the Brewer–Dobson circulation in the stratosphere and deep convection in the troposphere. Changes in deep convection associated with El Niño–Southern Oscillation (ENSO) reportedly have a small zonal mean effect on lower-stratospheric water vapor for strong zonally asymmetric effects on tropopause temperature. In contrast, IPWP events have zonally uniform imprints on tropopause temperature. This is because equatorial planetary waves forced by latent heat release from deep convection project strongly onto ENSO but weakly onto IPWP events.

scholarly journals Stratospheric water vapor trends in a coupled chemistry-climate model

2006 ◽  
Vol 33 (6) ◽  
Author(s):  
Wenshou Tian ◽  
Martyn P. Chipperfield
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
Stratospheric Water Vapor

Understanding the Changes of Stratospheric Water Vapor in Coupled Chemistry–Climate Model Simulations

2008 ◽  
Vol 65 (10) ◽  
pp. 3278-3291 ◽  
Author(s):  
Luke Oman ◽  
Darryn W. Waugh ◽  
Steven Pawson ◽  
Richard S. Stolarski ◽  
J. Eric Nielsen
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
First Century ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
Tropical Tropopause ◽  
Twenty First Century ◽  
Climate Model Simulations ◽  
Cold Point ◽  
Methane Concentrations

Past and future climate simulations from the Goddard Earth Observing System Chemistry–Climate Model (GEOS CCM), with specified boundary conditions for sea surface temperature, sea ice, and trace gas emissions, have been analyzed to assess trends and possible causes of changes in stratospheric water vapor. The simulated distribution of stratospheric water vapor in the 1990s compares well with observations. Changes in the cold point temperatures near the tropical tropopause can explain differences in entry stratospheric water vapor. The average saturation mixing ratio of a 20° latitude by 15° longitude region surrounding the minimum tropical saturation mixing ratio is shown to be a useful diagnostic for entry stratospheric water vapor and does an excellent job reconstructing the annual average entry stratospheric water vapor over the period 1950–2100. The simulated stratospheric water vapor increases over the 50 yr between 1950 and 2000, primarily because of changes in methane concentrations, offset by a slight decrease in tropical cold point temperatures. Stratospheric water vapor is predicted to continue to increase over the twenty-first century, with increasing methane concentrations causing the majority of the trend to midcentury. Small increases in cold point temperature cause increases in the entry water vapor throughout the twenty-first century. The increasing trend in future water vapor is tempered by a decreasing contribution of methane oxidation owing to cooling stratospheric temperatures and by increased tropical upwelling, leading to a near-zero trend for the last 30 yr of the twenty-first century.

Evolution of Water Vapor Concentrations and Stratospheric Age of Air in Coupled Chemistry-Climate Model Simulations

2007 ◽  
Vol 64 (3) ◽  
pp. 905-921 ◽  
Author(s):  
John Austin ◽  
John Wilson ◽  
Feng Li ◽  
Holger Vömel
Keyword(s):  
Water Vapor ◽  
Greenhouse Gas ◽  
Climate Model ◽  
Sea Surface ◽  
Time Slice ◽  
Sea Surface Temperatures ◽  
Model Simulations ◽  
Stratospheric Water Vapor ◽  
Surface Temperatures ◽  
Climate Model Simulations

Abstract Stratospheric water vapor concentrations and age of air are investigated in an ensemble of coupled chemistry-climate model simulations covering the period from 1960 to 2005. Observed greenhouse gas concentrations, halogen concentrations, aerosol amounts, and sea surface temperatures are all specified in the model as time-varying fields. The results are compared with two experiments (time-slice runs) with constant forcings for the years 1960 and 2000, in which the sea surface temperatures are set to the same climatological values, aerosol concentrations are fixed at background levels, while greenhouse gas and halogen concentrations are set to the values for the relevant years. The time-slice runs indicate an increase in stratospheric water vapor from 1960 to 2000 due primarily to methane oxidation. The age of air is found to be significantly less in the year 2000 run than the 1960 run. The transient runs from 1960 to 2005 indicate broadly similar results: an increase in water vapor and a decrease in age of air. However, the results do not change gradually. The age of air decreases significantly only after about 1975, corresponding to the period of ozone reduction. The age of air is related to tropical upwelling, which determines the transport of methane into the stratosphere. Oxidation of increased methane from enhanced tropical upwelling results in higher water vapor amounts. In the model simulations, the rate of increase of stratospheric water vapor during the period of enhanced upwelling is up to twice the long-term mean. The concentration of stratospheric water vapor also increases following volcanic eruptions during the simulations.

scholarly journals Impact of convectively lofted ice on the seasonal cycle of tropical lower stratospheric water vapor

2019 ◽  
Author(s):  
Xun Wang ◽  
Andrew E. Dessler ◽  
Mark R. Schoeberl ◽  
Wandi Yu ◽  
Tao Wang
Keyword(s):  
Water Vapor ◽  
Seasonal Cycle ◽  
Climate Model ◽  
Boreal Summer ◽  
Small Contribution ◽  
Asian Monsoon Region ◽  
Stratospheric Water Vapor ◽  
Trajectory Model ◽  
Tropical Tropopause ◽  
Important Region

Abstract. We use a forward Lagrangian trajectory model to diagnose mechanisms that produce the tropical lower stratospheric (LS) water vapor seasonal cycle observed by the Microwave Limb Sounder (MLS) and reproduced by the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM) in the tropical tropopause layer (TTL). We confirm in both the MLS and GEOSCCM that the seasonal cycle of water vapor is primarily determined by the seasonal cycle of TTL temperatures. However, we find that the seasonal cycle of temperature predicts a smaller seasonal cycle of LS water vapor between 10° N–40° N than observed by MLS. We show that including evaporation of convectively lofted ice in the trajectory model increases the simulated maximum value in the 10° N–40° N water vapor seasonal cycle by 1.9 ppmv (47 %) and increases the seasonal amplitude by 1.26 ppmv (123 %), which improves the prediction of LS water vapor annual cycle. We conclude that the moistening effect from convective ice evaporation in the TTL plays a key role regulating and maintaining the tropical LS water vapor seasonal cycle. Most of the convective moistening in the 10° N–40° N range comes from convective ice evaporation occurring at the same latitudes. A small contribution to the moistening comes from convective ice evaporation occurring between 10° S–10° N. Within 10° N–40° N, the Asian monsoon region is the most important region for convective ice evaporation and convective moistening during boreal summer and autumn.

scholarly journals Spectrally Dependent CLARREO Infrared Spectrometer Calibration Requirement for Climate Change Detection

2017 ◽  
Vol 30 (11) ◽  
pp. 3979-3998 ◽  
Author(s):  
Xu Liu ◽  
Wan Wu ◽  
Bruce A. Wielicki ◽  
Qiguang Yang ◽  
Susan H. Kizer ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Vapor ◽  
Climate Model ◽  
Model Simulation ◽  
Atmospheric Temperature ◽  
Reanalysis Data ◽  
Natural Variability ◽  
Radiometric Calibration ◽  
Climate Trends ◽  
Moisture Profiles

Abstract Detecting climate trends of atmospheric temperature, moisture, cloud, and surface temperature requires accurately calibrated satellite instruments such as the Climate Absolute Radiance and Refractivity Observatory (CLARREO). Previous studies have evaluated the CLARREO measurement requirements for achieving climate change accuracy goals in orbit. The present study further quantifies the spectrally dependent IR instrument calibration requirement for detecting trends of atmospheric temperature and moisture profiles. The temperature, water vapor, and surface skin temperature variability and the associated correlation time are derived using the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data. The results are further validated using climate model simulation results. With the derived natural variability as the reference, the calibration requirement is established by carrying out a simulation study for CLARREO observations of various atmospheric states under all-sky conditions. A 0.04-K (k = 2; 95% confidence) radiometric calibration requirement baseline is derived using a spectral fingerprinting method. It is also demonstrated that the requirement is spectrally dependent and that some spectral regions can be relaxed as a result of the hyperspectral nature of the CLARREO instrument. Relaxing the requirement to 0.06 K (k = 2) is discussed further based on the uncertainties associated with the temperature and water vapor natural variability and relatively small delay in the time to detect for trends relative to the baseline case. The methodology used in this study can be extended to other parameters (such as clouds and CO2) and other instrument configurations.

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