Surface warming patterns dominate the uncertainty in global water vapor plus lapse rate feedback

2020 ◽  
Vol 39 (3) ◽  
pp. 81-89 ◽  
Author(s):  
Jingchun Zhang ◽  
Jian Ma ◽  
Jing Che ◽  
Zhenqiang Zhou ◽  
Guoping Gao
Keyword(s):  
Water Vapor ◽  
Lapse Rate ◽  
Surface Warming ◽  
Rate Feedback ◽  
Global Water

scholarly journals Understanding the Differences Between TOA and Surface Energy Budget Attributions of Surface Warming

2021 ◽  
Vol 9 ◽  
Author(s):  
Sergio A. Sejas ◽  
Xiaoming Hu ◽  
Ming Cai ◽  
Hanjie Fan
Keyword(s):  
Surface Energy ◽  
Energy Budget ◽  
Surface Energy Budget ◽  
Lapse Rate ◽  
Climate Feedback ◽  
Energy Budgets ◽  
Response Analysis ◽  
Surface Warming ◽  
Rate Feedback ◽  
Consistent Picture

Energy budget decompositions have widely been used to evaluate individual process contributions to surface warming. Conventionally, the top-of-atmosphere (TOA) energy budget has been used to carry out such attribution, while other studies use the surface energy budget instead. However, the two perspectives do not provide the same interpretation of process contributions to surface warming, particularly when executing a spatial analysis. These differences cloud our understanding and inhibit our ability to shrink the inter-model spread. Changes to the TOA energy budget are equivalent to the sum of the changes in the atmospheric and surface energy budgets. Therefore, we show that the major discrepancies between the surface and TOA perspectives are due to non-negligible changes in the atmospheric energy budget that differ from their counterparts at the surface. The TOA lapse-rate feedback is the manifestation of multiple processes that produce a vertically non-uniform warming response such that it accounts for the asymmetry between the changes in the atmospheric and surface energy budgets. Using the climate feedback-response analysis method, we are able to decompose the lapse-rate feedback into contributions by individual processes. Combining the process contributions that are hidden within the lapse-rate feedback with their respective direct impacts on the TOA energy budget allows for a very consistent picture of process contributions to surface warming and its inter-model spread as that given by the surface energy budget approach.

scholarly journals An Assessment of the Primary Sources of Spread of Global Warming Estimates from Coupled Atmosphere–Ocean Models

2008 ◽  
Vol 21 (19) ◽  
pp. 5135-5144 ◽  
Author(s):  
Jean-Louis Dufresne ◽  
Sandrine Bony
Keyword(s):  
Global Warming ◽  
Water Vapor ◽  
General Circulation ◽  
Lapse Rate ◽  
Climate Feedback ◽  
Ocean Heat Uptake ◽  
Feedback Analysis ◽  
Cloud Feedbacks ◽  
Rate Feedback ◽  
Heat Uptake

Abstract Climate feedback analysis constitutes a useful framework for comparing the global mean surface temperature responses to an external forcing predicted by general circulation models (GCMs). Nevertheless, the contributions of the different radiative feedbacks to global warming (in equilibrium or transient conditions) and their comparison with the contribution of other processes (e.g., the ocean heat uptake) have not been quantified explicitly. Here these contributions from the classical feedback analysis framework are defined and quantified for an ensemble of 12 third phase of the Coupled Model Intercomparison Project (CMIP3)/Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) coupled atmosphere–ocean GCMs. In transient simulations, the multimodel mean contributions to global warming associated with the combined water vapor–lapse-rate feedback, cloud feedback, and ocean heat uptake are comparable. However, intermodel differences in cloud feedbacks constitute by far the most primary source of spread of both equilibrium and transient climate responses simulated by GCMs. The spread associated with intermodel differences in cloud feedbacks appears to be roughly 3 times larger than that associated either with the combined water vapor–lapse-rate feedback, the ocean heat uptake, or the radiative forcing.

scholarly journals An Assessment of Climate Feedbacks in Coupled Ocean–Atmosphere Models

2006 ◽  
Vol 19 (14) ◽  
pp. 3354-3360 ◽  
Author(s):  
Brian J. Soden ◽  
Isaac M. Held
Keyword(s):  
Water Vapor ◽  
Temperature Response ◽  
Lapse Rate ◽  
Climate Feedbacks ◽  
Regional Patterns ◽  
Surface Warming ◽  
Ocean Atmosphere ◽  
Tightly Coupled ◽  
Vertical Changes ◽  
Water Vapor Mixing Ratio

Abstract The climate feedbacks in coupled ocean–atmosphere models are compared using a coordinated set of twenty-first-century climate change experiments. Water vapor is found to provide the largest positive feedback in all models and its strength is consistent with that expected from constant relative humidity changes in the water vapor mixing ratio. The feedbacks from clouds and surface albedo are also found to be positive in all models, while the only stabilizing (negative) feedback comes from the temperature response. Large intermodel differences in the lapse rate feedback are observed and shown to be associated with differing regional patterns of surface warming. Consistent with previous studies, it is found that the vertical changes in temperature and water vapor are tightly coupled in all models and, importantly, demonstrate that intermodel differences in the sum of lapse rate and water vapor feedbacks are small. In contrast, intermodel differences in cloud feedback are found to provide the largest source of uncertainty in current predictions of climate sensitivity.

scholarly journals The Vertical Structure of Tropospheric Water Vapor: Comparing Radiative and Ocean-Driven Climate Changes

2016 ◽  
Vol 29 (11) ◽  
pp. 4251-4268 ◽  
Author(s):  
Brian E. J. Rose ◽  
M. Cameron Rencurrel
Keyword(s):  
Water Vapor ◽  
Surface Temperature ◽  
Diagnostic Technique ◽  
Lapse Rate ◽  
Ocean Heat Uptake ◽  
Surface Warming ◽  
Wide Range ◽  
Single Column ◽  
Transient Climate Change ◽  
Lapse Rates

Abstract Changes in column-integrated water vapor (Q) in response to increased CO2 and ocean heat uptake (OHU) are investigated in slab-ocean aquaplanet simulations. The simulations span a wide range of warming and moistening patterns due to the spatial structures of the imposed OHU. Fractional changes in Q per degree of surface warming range from 0% to 20% K−1 locally and from 3.6% to 11% K−1 globally. A new diagnostic technique decomposes these changes into relative humidity (RH), surface temperature, and lapse rate contributions. Single-column calculations demonstrate substantial departures from apparent (surface temperature based) Clausius–Clapeyron (CC) scaling due to lapse rates changes; a moist-adiabatic column with fixed, uniform RH exceeds the CC rate by 2.5% K−1. The RH contribution is very small in most simulations. The various Q scalings are thus all consistent CC, but result from different patterns of polar amplification and lapse rate change. Lapse rates are sensitive to location and magnitude of OHU, with implications for Q under transient climate change. CO2 with subpolar (tropical) OHU results in higher (lower) Q scalings than CO2 alone. The weakest Q scaling (and largest RH effects) is found for increased poleward ocean heat transport, which causes strongly polar-amplified warming and near-zero tropical temperature change. Despite weak RH changes and fidelity to the CC relation, Q is expected to vary widely on different time scales in nature due to sensitivity of lapse rates to OHU along with the nonlinearity of the diagnostics.

Radiative feedbacks in a 1D radiative-convective equilibrium model

2020 ◽  
Author(s):  
Lukas Kluft ◽  
Sally Dacie ◽  
Stefan A. Buehler ◽  
Hauke Schmidt ◽  
Bjorn Stevens
Keyword(s):  
Water Vapor ◽  
Climate Models ◽  
Lapse Rate ◽  
Transfer Model ◽  
Electromagnetic Spectrum ◽  
Optical Parameters ◽  
Climate Modelling ◽  
Rate Feedback ◽  
Radiative Feedbacks ◽  
Radiation Scheme

<p><span>Equilibrium climate sensitivity (ECS), the change in surface temperature in response to a doubling of atmospheric CO2, is arguably one of the most important quantities when discussing climate change. Despite major improvements in climate modelling over the last decades, ECS estimates lie within a rather constant range between 1.5-4 K. The cause of this spread is not obvious as the comparison of comprehensive climate models is difficult due to the complexity of their formulations.</span></p><p> </p><p><span>We are revisiting one of the simplest climate models, one-dimensional radiative-convective equilibrium (RCE). Despite their simple and concise model formulation, RCE models include the most dominant clear-sky radiative feedbacks. In our study, we quantify the strength of the Planck, water-vapor, and lapse-rate feedback by turning them on or off using different model configurations. This method allows us to compare the effect of different model assumptions, e.g. the vertical distribution of water vapor, on the decomposed radiative feedbacks. We find that the interplay of the water-vapor and the lapse-rate feedback is especially affected by the relative humidity in the upper troposphere.</span></p><p> </p><p><span>The RCE model is run with a state-of-the-art radiation scheme, that is also used in comprehensive<span>  </span>Earth system models. A line-by-line radiative transfer model is used to both verify the performance of the fast radiation scheme, and to attribute changes in the radiative feedbacks to specific regions in the electromagnetic spectrum.</span></p><p> </p><p><span>In a further step, conceptual rectangular clouds are added to investigate possible cloud masking effects on both the radiative forcing and feedback. A large Monte Carlo ensemble is used to tune the cloud optical parameters in a way that the resulting cloud radiative effect matches satellite observations. Preliminary results suggest a near zero long-wave feedback, in contrast to previous studies.</span></p>

scholarly journals Physical Mechanisms of Tropical Climate Feedbacks Investigated Using Temperature and Moisture Trends*

2015 ◽  
Vol 28 (22) ◽  
pp. 8968-8987 ◽  
Author(s):  
A. J. Ferraro ◽  
F. H. Lambert ◽  
M. Collins ◽  
G. M. Miles
Keyword(s):  
Water Vapor ◽  
Climate Models ◽  
Tropical Climate ◽  
Lapse Rate ◽  
Climate Feedback ◽  
Climate Projections ◽  
Tropospheric Temperature ◽  
Regional Pattern ◽  
Rate Feedback ◽  
Water Vapor Feedback

Abstract Tropical climate feedback mechanisms are assessed using satellite-observed and model-simulated trends in tropical tropospheric temperature from the MSU/AMSU instruments and upper-tropospheric humidity from the HIRS instruments. Despite discrepancies in the rates of tropospheric warming between observations and models, both are consistent with constant relative humidity over the period 1979–2008. Because uncertainties in satellite-observed tropical-mean trends preclude a constraint on tropical-mean trends in models regional features of the feedbacks are also explored. The regional pattern of the lapse rate feedback is primarily determined by the regional pattern of surface temperature changes, as tropical atmospheric warming is relatively horizontally uniform. The regional pattern of the water vapor feedback is influenced by the regional pattern of precipitation changes, with variations of 1–2 W m−2 K−1 across the tropics (compared to a tropical-mean feedback magnitude of 3.3–4 W m−2 K−1). Thus the geographical patterns of water vapor and lapse rate feedbacks are not correlated, but when the feedbacks are calculated in precipitation percentiles rather than in geographical space they are anticorrelated, with strong positive water vapor feedback associated with strong negative lapse rate feedback. The regional structure of the feedbacks is not related to the strength of the tropical-mean feedback in a subset of the climate models from the CMIP5 archive. Nevertheless the approach constitutes a useful process-based test of climate models and has the potential to be extended to constrain regional climate projections.

scholarly journals Sensitivity of Polar Amplification to Varying Insolation Conditions

2018 ◽  
Vol 31 (12) ◽  
pp. 4933-4947 ◽  
Author(s):  
Doyeon Kim ◽  
Sarah M. Kang ◽  
Yechul Shin ◽  
Nicole Feldl
Keyword(s):  
Energy Transport ◽  
Longwave Radiation ◽  
Atmospheric Model ◽  
Static Stability ◽  
Lapse Rate ◽  
Polar Surface ◽  
Surface Warming ◽  
Polar Amplification ◽  
Rate Feedback ◽  
Radiative Feedbacks

The mechanism of polar amplification in the absence of surface albedo feedback is investigated using an atmospheric model coupled to an aquaplanet slab ocean forced by a CO2 doubling. In particular, we examine the sensitivity of polar surface warming response under different insolation conditions from equinox (EQN) to annual mean (ANN) to seasonally varying (SEA). Varying insolation greatly affects the climatological static stability. The equinox condition, with the largest polar static stability, exhibits a bottom-heavy vertical profile of polar warming response that leads to the strongest polar amplification. In contrast, the polar warming response in ANN and SEA exhibits a maximum in the midtroposphere, which leads to only weak polar amplification. The midtropospheric warming maximum, which results from an increased poleward atmospheric energy transport in response to the tropics-to-pole energy imbalance, contributes to polar surface warming via downward clear-sky longwave radiation. However, it is cancelled by negative cloud radiative feedbacks locally. Furthermore, the polar lapse rate feedback, calculated from radiative kernels, is negative due to the midtropospheric warming maximum, and hence is not able to promote the polar surface warming. On the other hand, the polar lapse rate feedback in EQN is positive due to the bottom-heavy warming response, contributing to the strong polar surface warming. This contrast suggests that locally induced positive radiative feedbacks are necessary for strong polar amplification. Our results demonstrate how interactions among climate feedbacks determine the strength of polar amplification.

Sources of Intermodel Spread in the Lapse Rate and Water Vapor Feedbacks

2018 ◽  
Vol 31 (8) ◽  
pp. 3187-3206 ◽  
Author(s):  
Stephen Po-Chedley ◽  
Kyle C. Armour ◽  
Cecilia M. Bitz ◽  
Mark D. Zelinka ◽  
Benjamin D. Santer ◽  
...  
Keyword(s):  
Water Vapor ◽  
Sea Ice ◽  
General Circulation ◽  
Large Scale ◽  
General Circulation Models ◽  
Lapse Rate ◽  
Cross Model ◽  
Surface Warming ◽  
Antarctic Sea Ice ◽  
The Tropics

Abstract Sources of intermodel differences in the global lapse rate (LR) and water vapor (WV) feedbacks are assessed using CO2 forcing simulations from 28 general circulation models. Tropical surface warming leads to significant warming and moistening in the tropical and extratropical upper troposphere, signifying a nonlocal, tropical influence on extratropical radiation and feedbacks. Model spread in the locally defined LR and WV feedbacks is pronounced in the Southern Ocean because of large-scale ocean upwelling, which reduces surface warming and decouples the surface from the tropospheric response. The magnitude of local extratropical feedbacks across models and over time is well characterized using the ratio of tropical to extratropical surface warming. It is shown that model differences in locally defined LR and WV feedbacks, particularly over the southern extratropics, drive model variability in the global feedbacks. The cross-model correlation between the global LR and WV feedbacks therefore does not arise from their covariation in the tropics, but rather from the pattern of warming exerting a common control on extratropical feedback responses. Because local feedbacks over the Southern Hemisphere are an important contributor to the global feedback, the partitioning of surface warming between the tropics and the southern extratropics is a key determinant of the spread in the global LR and WV feedbacks. It is also shown that model Antarctic sea ice climatology influences sea ice area changes and southern extratropical surface warming. As a result, model discrepancies in climatological Antarctic sea ice area have a significant impact on the intermodel spread of the global LR and WV feedbacks.

scholarly journals The Sensitivity of the Hydrological Cycle to Internal Climate Variability versus Anthropogenic Climate Change

2016 ◽  
Vol 29 (10) ◽  
pp. 3661-3673 ◽  
Author(s):  
Ryan J. Kramer ◽  
Brian J. Soden
Keyword(s):  
Water Vapor ◽  
Time Scales ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Internal Variability ◽  
Radiative Cooling ◽  
Surface Warming ◽  
Internal Climate Variability ◽  
Radiative Processes ◽  
Global Mean

Abstract In response to rising CO2 concentrations, climate models predict that globally averaged precipitation will increase at a much slower rate than water vapor. However, some observational studies suggest that global-mean precipitation and water vapor have increased at similar rates. While the modeling results emphasize changes at multidecadal time scales where the anthropogenic signal dominates, the shorter observational record is more heavily influenced by internal variability. Whether the physical constraints on the hydrological cycle fundamentally differ between these time scales is investigated. The results of this study show that while global-mean precipitation is constrained by radiative cooling on both time scales, the effects of CO2 dominate on multidecadal time scales, acting to suppress the increase in radiative cooling with warming. This results in a smaller precipitation change compared to interannual time scales where the effects of CO2 forcing are small. It is also shown that intermodel spread in the response of atmospheric radiative cooling (and thus global-mean precipitation) to anthropogenically forced surface warming is dominated by clear-sky radiative processes and not clouds, while clouds dominate under internal variability. The findings indicate that the sensitivity of the global hydrological cycle to surface warming differs fundamentally between internal variability and anthropogenically forced changes and this has important implications for interpreting observations of the hydrological sensitivity.

Global water vapor content decreases from 2003 to 2012: An analysis based on MODIS data

2017 ◽  
Vol 27 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kebiao Mao ◽  
Jingming Chen ◽  
Zhaoliang Li ◽  
Ying Ma ◽  
Yang Song ◽  
...  
Keyword(s):  
Water Vapor ◽  
Water Vapor Content ◽  
Modis Data ◽  
Global Water
Sign in / Sign up

Export Citation Format

Share Document