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.

scholarly journals Clausius–Clapeyron Scaling of CAPE from Analytical Solutions to RCE

2016 ◽  
Vol 73 (9) ◽  
pp. 3719-3737 ◽  
Author(s):  
David M. Romps
Keyword(s):  
Surface Temperature ◽  
Analytical Solutions ◽  
Convective Available Potential Energy ◽  
Specific Humidity ◽  
Tropopause Height ◽  
Surface Warming ◽  
Surface Temperatures ◽  
Humidity Change ◽  
Rate Of Increase ◽  
Wide Range

Abstract By deriving analytical solutions to radiative–convective equilibrium (RCE), it is shown mathematically that convective available potential energy (CAPE) exhibits Clausius–Clapeyron (CC) scaling over a wide range of surface temperatures up to 310 K. Above 310 K, CAPE deviates from CC scaling and even decreases with warming at very high surface temperatures. At the surface temperature of the current tropics, the analytical solutions predict that CAPE increases at a rate of about 6%–7% per kelvin of surface warming. The analytical solutions also provide insight on how the tropopause height and stratospheric humidity change with warming. Changes in the tropopause height exhibit CC scaling, with the tropopause rising by about 400 m per kelvin of surface warming at current tropical temperatures and by about 1–2 km K−1 at surface temperatures in the range of 320–340 K. The specific humidity of the stratosphere exhibits super-CC scaling at temperatures moderately warmer than the current tropics. With a surface temperature of the current tropics, the stratospheric specific humidity increases by about 6% per kelvin of surface warming, but the rate of increase is as high as 30% K−1 at warmer surface temperatures.

scholarly journals Geographical Distribution of Climate Feedbacks in the NCAR CCSM3.0

2011 ◽  
Vol 24 (11) ◽  
pp. 2737-2753 ◽  
Author(s):  
Patrick C. Taylor ◽  
Robert G. Ellingson ◽  
Ming Cai
Keyword(s):  
Water Vapor ◽  
Spatial Variability ◽  
Surface Temperature ◽  
Spatial Patterns ◽  
Temperature Response ◽  
Lapse Rate ◽  
Strongly Correlated ◽  
Climate Feedbacks ◽  
Net Flux ◽  
Radiative Perturbation

Abstract This study performs offline, partial radiative perturbation calculations to determine the geographical distributions of climate feedbacks contributing to the top-of-atmosphere (TOA) radiative energy budget. These radiative perturbations are diagnosed using monthly mean model output from the NCAR Community Climate System Model version 3 (CCSM3.0) forced with the Special Report Emissions Scenario (SRES) A1B emission scenario. The Monte Carlo Independent Column Approximation (MCICA) technique with a maximum–random overlap rule is used to sample monthly mean cloud frequency profiles to perform the radiative transfer calculations. It is shown that the MCICA technique provides a good estimate of all feedback sensitivity parameters. The radiative perturbation results are used to investigate the spatial variability of model feedbacks showing that the shortwave cloud and lapse rate feedbacks exhibit the most and second most spatial variability, respectively. It has been shown that the model surface temperature response is highly correlated with the change in the TOA net flux, and that the latter is largely determined by the total feedback spatial pattern rather than the external forcing. It is shown by representing the change in the TOA net flux as a linear combination of individual feedback radiative perturbations that the lapse rate explains the most spatial variance of the surface temperature response. Feedback spatial patterns are correlated with the model response and other feedback spatial patterns to investigate these relationships. The results indicate that the model convective response is strongly correlated with cloud and water vapor feedbacks, but the lapse rate feedback geographic distribution is strongly correlated with the climatological distribution of convection. The implication for the water vapor–lapse rate anticorrelation is discussed.

scholarly journals A Physically-Constrained Calibration Database for Land Surface Temperature Using Infrared Retrieval Algorithms

2016 ◽  
Author(s):  
João P. A. Martins ◽  
Isabel F. Trigo ◽  
Virgílio A. Bento ◽  
Carlos da Camara
Keyword(s):  
Water Vapor ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Dynamic Range ◽  
Single Channel ◽  
Level Structure ◽  
Full Range ◽  
Wide Range ◽  
Total Column

Land Surface Temperature (LST) is routinely retrieved from remote sensing instruments using semi-empirical relationships between top of atmosphere (TOA) radiances and LST, using ancillary data such as total column water vapor or emissivity. These algorithms are calibrated using a set of forward radiative transfer simulations that return the TOA radiances given the LST and the thermodynamic profiles. The simulations are done in order to cover a wide range of surface and atmospheric conditions and viewing geometries. This work analyses calibration strategies, considering some of the most critical factors that need to be taken into account when building a calibration dataset, covering the full dynamic range of relevant variables. A sensitivity analysis of split-windows and single channel algorithms revealed that selecting a set of atmospheric profiles that spans the full range of surface temperatures and total column water vapor combinations that are physically possible seems beneficial for the quality of the regression model. However, the calibration is extremely sensitive to the low-level structure of the atmosphere indicating that the presence of atmospheric boundary layer features such as temperature inversions or strong vertical gradients of thermodynamic properties may affect LST retrievals in a non-trivial way. This article describes the criteria established in the EUMETSAT Land Surface Analysis – Satellite Application Facility to calibrate its LST algorithms applied both for current and forthcoming sensors.

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 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 Aerosol lifetime and climate change

2012 ◽  
Vol 12 (7) ◽  
pp. 16493-16514 ◽  
Author(s):  
G.-J. Roelofs
Keyword(s):  
Climate Change ◽  
Water Vapor ◽  
Climate Sensitivity ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Lapse Rate ◽  
Fundamental Relation ◽  
Wide Range

Abstract. The dominant removal mechanism for atmospheric aerosol is activation of particles to cloud droplets and subsequent wet deposition in precipitation. The atmospheric lifetime of aerosol is thus closely coupled to the atmospheric cycling time of water vapor. Changes of hydrological cycle characteristics resulting from climate change therefore directly affect aerosol lifetime, and thus the radiative forcing exerted by aerosol. This study expresses the coupling between water vapor and aerosol lifetimes and their temperature sensitivities in fundamental equations and in terms of the efficiency of processing of air by precipitating clouds. Based on climate model simulations these temperature sensitivities are estimated to be on the order of +5.3% K−1, but this may be an overestimation. Generally, shifting spatial and temporal patterns of aerosol (precursor) emissions and precipitation, and changes in aerosol activation efficiency probably influence aerosol lifetimes more than climate change itself, resulting in a wide range of simulated aerosol lifetime sensitivities between aerosol-climate models. It is possible that the climate sensitivity of models plays a role. It can be argued that climate sensitivity is intrinsically coupled with the simulated (temperature sensitivity of the) aerosol lifetime through the distribution of water vapor and aerosol between the lower and upper troposphere. This implies a fundamental relation between various feedback forcings (water vapor, lapse rate, cloud) and the aerosol forcing, illustrating the key role of the hydrological cycle in different aspects of the climate system.

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 Research Note:Derivation of temperature lapse rates in semi-arid south-eastern Arizona

2004 ◽  
Vol 8 (6) ◽  
pp. 1179-1185 ◽  
Author(s):  
R. C. Harlow ◽  
E. J. Burke ◽  
R. L. Scott ◽  
W. J. Shuttleworth ◽  
C. M. Brown ◽  
...  
Keyword(s):  
Regional Scale ◽  
Basin And Range ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Near Surface ◽  
South Eastern ◽  
Wide Range ◽  
The Mean ◽  
Lapse Rates ◽  
Semi Arid

Abstract. Ecological and hydrological modelling at the regional scale requires distributed information on weather variables, and temperature is important among these. In an area of basin and range topography with a wide range of elevations, such as south-eastern Arizona, measurements are usually available only at a relatively small number of locations and elevations, and temperatures elsewhere must be estimated from atmospheric lapse rate. This paper derives the lapse rates to estimate maximum, minimum and mean daily temperatures from elevation. Lapse rates were calculated using air temperatures at 2 m collected during 2002 at 18 locations across south-eastern Arizona, with elevations from 779 to 2512 m. The lapse rate predicted for the minimum temperature was lower than the mean environmental lapse rate (MELR), i.e. 6 K km–1, whereas those predicted for the mean and maximum daily temperature were very similar to the MELR. Lapse rates were also derived from radiosonde data at 00 and 12 UTC (5 pm and 5 am local time, respectively). The lapse rates calculated from radiosonde data were greater than those from the 2 m measurements, presumably because the effect of the surface was less. Given temperatures measured at Tucson airport, temperatures at the other sites were predicted using the different estimates of lapse rates. The best predictions of temperatures used the locally predicted lapse rates. In the case of maximum and mean temperature, using the MELR also resulted in accurate predictions. Keywords: near surface lapse rates, semi-arid climate, mean minimum and maximum temperatures, basin and range topography

scholarly journals Decomposing the Drivers of Polar Amplification with a Single Column Model

2020 ◽  
pp. 1-33
Author(s):  
Matthew Henry ◽  
Timothy M. Merlis ◽  
Nicholas J. Lutsko ◽  
Brian E.J. Rose
Keyword(s):  
General Circulation ◽  
Energy Transport ◽  
Circulation Model ◽  
Lapse Rate ◽  
Arctic Amplification ◽  
Polar Surface ◽  
Surface Warming ◽  
Column Model ◽  
Single Column ◽  
Single Column Model

AbstractThe precise mechanisms driving Arctic amplification are still under debate. Previous attribution methods compute the vertically-uniform temperature change required to balance the top-of-atmosphere energy imbalance caused by each forcing and feedback, with any departures from vertically-uniform warming collected into the lapse-rate feedback. We propose an alternative attribution method using a single column model that accounts for the forcing-dependence of high latitude lapse-rate changes. We examine this method in an idealized General Circulation Model (GCM), finding that, even though the column-integrated carbon dioxide (CO2) forcing and water vapor feedback are stronger in the tropics, they contribute to polar-amplified surface warming as they produce bottom-heavy warming in high latitudes. A separation of atmospheric temperature changes into local and remote contributors shows that, in the absence of polar surface forcing (e.g., sea-ice retreat), changes in energy transport are primarily responsible for the polar amplified pattern of warming. The addition of surface forcing substantially increases polar surface warming and reduces the contribution of atmospheric dry static energy transport to the warming. This physically-based attribution method can be applied to comprehensive GCMs to provide a clearer view of the mechanisms behind Arctic amplification.

scholarly journals Influences of Local and Remote Conditions on Tropical Precipitation and Its Response to Climate Change

2020 ◽  
Vol 33 (10) ◽  
pp. 4045-4063
Author(s):  
Marion Saint-Lu ◽  
Robin Chadwick ◽  
F. Hugo Lambert ◽  
Matthew Collins ◽  
Ian Boutle ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
General Circulation ◽  
Large Scale ◽  
Circulation Pattern ◽  
General Circulation Models ◽  
Overturning Circulation ◽  
Surface Warming ◽  
Single Column ◽  
Precipitation Changes

AbstractBy comparing a single-column model (SCM) with closely related general circulation models (GCMs), precipitation changes that can be diagnosed from local changes in surface temperature (TS) and relative humidity (RHS) are separated from more complex responses. In the SCM setup, the large-scale tropical circulation is parameterized to respond to the surface temperature departure from a prescribed environment, following the weak temperature gradient (WTG) approximation and using the damped gravity wave (DGW) parameterization. The SCM is also forced with moisture variations. First, it is found that most of the present-day mean tropical rainfall and circulation pattern is associated with TS and RHS patterns. Climate change experiments with the SCM are performed, imposing separately surface warming and CO2 increase. The rainfall responses to future changes in sea surface temperature patterns and plant physiology are successfully reproduced, suggesting that these are direct responses to local changes in convective instability. However, the SCM increases oceanic rainfall too much, and fails to reproduce the land rainfall decrease, both of which are associated with uniform ocean warming. It is argued that remote atmospheric teleconnections play a crucial role in both weakening the atmospheric overturning circulation and constraining precipitation changes. Results suggest that the overturning circulation weakens, both as a direct local response to increased CO2 and in response to energy-imbalance driven exchanges between ascent and descent regions.

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