Environmental Response in Coupled Energy and Water Cloud Impact Parameters Derived from A-Train Satellite, ERA-Interim and MERRA-2

2021 ◽  
Keyword(s):  
Climate Models ◽  
Water Cycle ◽  
Cloud Microphysics ◽  
Dynamic Regime ◽  
Radiative Heating ◽  
Radiative Effects ◽  
Surface Cooling ◽  
Heating Efficiency ◽  
Cloud Radiative Effects ◽  
Impact Parameters

Abstract Understanding the connections between latent heating from precipitation and cloud radiative effects is essential for accurately parameterizing cross-scale links between cloud microphysics and global energy and water cycles in climate models. While commonly examined separately, this study adopts two cloud impact parameters (CIPs), the surface radiative cooling efficiency, Rc, and atmospheric radiative heating efficiency, Rh, that explicitly couple cloud radiative effects and precipitation to characterize how efficiently precipitating cloud systems influence the energy budget and water cycle using A-Train observations and two reanalyses. These CIPs exhibit distinct global distributions that suggest cloud energy and water cycle coupling are highly dependent on cloud regime. The dynamic regime (ω500) controls the sign of Rh, while column water vapor (CWV) appears to be the larger control on the magnitude. The magnitude of Rc is highly coupled to the dynamic regime. Observations show that clouds cool the surface very efficiently per unit rainfall at both low and high sea surface temperature (SST) and CWV, but reanalyses only capture the former. Reanalyses fail to simulate strong Rh and moderate Rc in deep convection environments but produce stronger Rc and Rh than observations in shallow, warm rain systems in marine stratocumulus regions. While reanalyses generate fairly similar climatologies in the frequency of environmental states, the response of Rc and Rh to SST and CWV results in systematic differences in zonal and meridional gradients of cloud atmospheric heating and surface cooling relative to A-Train observations that may have significant implications for global circulations and cloud feedbacks.

scholarly journals The cloud-free global energy balance and inferred cloud radiative effects: an assessment based on direct observations and climate models

2018 ◽  
Vol 52 (7-8) ◽  
pp. 4787-4812 ◽  
Author(s):  
Martin Wild ◽  
Maria Z. Hakuba ◽  
Doris Folini ◽  
Patricia Dörig-Ott ◽  
Christoph Schär ◽  
...  
Keyword(s):  
Energy Balance ◽  
Climate Models ◽  
Radiative Effects ◽  
Global Energy ◽  
Global Energy Balance ◽  
Direct Observations ◽  
Cloud Radiative Effects

scholarly journals Monte Carlo-based subgrid parameterization of vertical velocity and stratiform cloud microphysics in ECHAM5.5-HAM2

2013 ◽  
Vol 13 (2) ◽  
pp. 5477-5507
Author(s):  
J. Tonttila ◽  
P. Räisänen ◽  
H. Järvinen
Keyword(s):  
Monte Carlo ◽  
Vertical Velocity ◽  
Cloud Droplet ◽  
Cloud Microphysics ◽  
Radiative Effects ◽  
Cloud Droplets ◽  
Microphysical Properties ◽  
Cloud Radiative Effects ◽  
Cloud Activation ◽  
The Impact

Abstract. A new method for parameterizing the subgrid variations of vertical velocity and cloud droplet number concentration (CDNC) is presented for GCMs. These parameterizations build on top of existing parameterizations that create stochastic subgrid cloud columns inside the GCM grid-cells, which can be employed by the Monte Carlo independent column approximation approach for radiative transfer. The new model version adds a description for vertical velocity in individual subgrid columns, which can be used to compute cloud activation and the subgrid distribution of the number of cloud droplets explicitly. This provides a consistent way for simulating the cloud radiative effects with two-moment cloud microphysical properties defined in subgrid-scale. The primary impact of the new parameterizations is to decrease the CDNC over polluted continents, while over the oceans the impact is smaller. This promotes changes in the global distribution of the cloud radiative effects and might thus have implications on model estimation of the indirect radiative effect of aerosols.

scholarly journals Performance of McRAS-AC in the GEOS-5 AGCM: aerosol-cloud-microphysics, precipitation, cloud radiative effects, and circulation

2012 ◽  
Vol 5 (2) ◽  
pp. 1381-1434 ◽  
Author(s):  
Y. C. Sud ◽  
D. Lee ◽  
L. Oreopoulos ◽  
D. Barahona ◽  
A. Nenes ◽  
...  
Keyword(s):  
Climate Modeling ◽  
Cloud Model ◽  
Cloud Microphysics ◽  
Sensitivity Analyses ◽  
Radiative Effects ◽  
Boundary Layer Clouds ◽  
Aerosol Cloud ◽  
Marine Stratus ◽  
Systematic Biases ◽  
Cloud Radiative Effects

Abstract. A revised version of the Microphysics of clouds with Relaxed Arakawa-Schubert and Aerosol-Cloud interaction scheme (McRAS-AC) including, among others, the Barahona and Nenes ice nucleation parameterization, is implemented in the GEOS-5 AGCM. Various fields from a 10-yr long integration of the AGCM with McRAS-AC were compared with their counterparts from an integration of the baseline GEOS-5 AGCM using satellite data as observations. Generally McRAS-AC simulations have smaller biases in cloud fields and cloud radiative effects over most of the regions of the Earth than the baseline GEOS-5 AGCM. Two systematic biases are identified in the McRAS-AC runs: one under-prediction of cloud particles around 40° S–60° S, and one over-prediction of cloud water path during Northern Hemisphere summer over the Gulf Stream and North Pacific. Sensitivity analyses show that these biases potentially originate from biases in the aerosol input. The first bias is largely eliminated in a sensitivity test using 50% smaller sea-salt aerosol particles, while the second bias is much reduced when interactive aerosol chemistry was turned on. The main drawback of McRAS-AC is dearth of low-level marine stratus clouds, probably due to lack of boundary-layer clouds that is an outcome of explicit dry-convection not yet implemented into the cloud model. Nevertheless, McRAS-AC simulates realistic clouds and their optical properties that can further improve with better aerosol-input. Thereby, McRAS-AC has the potential to be a valuable tool for climate modeling research because of its superior simulation capabilities that physically couple aerosols, cloud microphysics, cloud macrophysics, and cloud-radiation interaction for all clouds.

scholarly journals Cloud Radiative Effects and Precipitation in Extratropical Cyclones

2016 ◽  
Vol 29 (18) ◽  
pp. 6483-6507 ◽  
Author(s):  
James B. Polly ◽  
William B. Rossow
Keyword(s):  
Radiative Heating ◽  
Extratropical Cyclones ◽  
Radiative Effects ◽  
Local Pressure ◽  
Wind Speeds ◽  
Modeling Analysis ◽  
Flux Profile ◽  
Pressure Anomaly ◽  
Cloud Radiative Effects ◽  
Sky Conditions

Abstract Clouds associated with extratropical cyclones complicate the well-developed theory of dry baroclinic waves through feedback on their dynamics by precipitation and cloud-altered radiative heating. The relationships between cyclone characteristics and the diabatic heating associated with cloud radiative effects (CREs) and latent heat release remain unclear. A cyclone tracking algorithm [NASA’s Modeling, Analysis, and Prediction (MAP) Climatology of Midlatitude Storminess (MCMS)] is used to identify over 106 cyclones in 33 years of the ERA-Interim and collect the properties of each disturbance. Considering storm intensity as related to wind speeds, which depend on the pressure gradient, the distribution of cyclone properties is investigated using groups defined by their depth (local pressure anomaly) and the radius of the region within closed pressure contours to investigate variations with longitude (especially ocean and land), hemisphere, and season. Using global data products of cloud radiative effects on in-atmosphere net radiation [the ISCCP radiative flux profile dataset (ISCCP-FD)] and precipitation (GPCP), composites are assembled for each cyclone group and for “nonstormy” locations. On average, the precipitation rate and the CRE are approximately the same among all cyclone groups and do not strongly differ from nonstormy conditions. The variance of both precipitation and CRE increases with cyclone size and depth. In larger, deeper storms, maximum precipitation and CRE increase, but so do the amounts of nonprecipitating and clear-sky conditions.

scholarly journals Differences in tropical high clouds among reanalyses: origins and radiative impacts

2020 ◽  
Author(s):  
Jonathon S. Wright ◽  
Xiaoyi Sun ◽  
Paul Konopka ◽  
Kirstin Krüger ◽  
Andrea M. Molod ◽  
...  
Keyword(s):  
Water Content ◽  
Lower Stratosphere ◽  
Cloud Water ◽  
Radiative Heating ◽  
The Other ◽  
Radiative Effects ◽  
High Cloud ◽  
Cloud Water Content ◽  
Cloud Radiative Effects ◽  
The Tropics

Abstract. We examine differences among reanalysis high cloud products in the tropics, assess the impacts of these differences on radiation budgets at the top of the atmosphere and within the tropical upper troposphere and lower stratosphere (UTLS), and discuss their possible origins in the context of the reanalysis models. We focus on the ERA5, ERA-Interim, JRA-55, MERRA-2, and CFSR/CFSv2 reanalyses, with MERRA included in selected comparisons. As a general rule, JRA-55 produces the smallest tropical high cloud fractions and cloud water contents among the reanalyses, while MERRA-2 produces the largest. Accordingly, cloud radiative effects are relatively weak in JRA-55 and relatively strong in MERRA-2. Only MERRA-2 and ERA5 among the reanalyses produce tropical-mean values of outgoing longwave radiation (OLR) close to observed, but ERA5 tends to underestimate cloud effects while MERRA-2 tends to overestimate variability. ERA5 also produces distributions of longwave, shortwave, and total cloud radiative effects at top-of-atmosphere that are very consistent with observed. The other reanalyses all exhibit substantial biases in at least one of these metrics, although compensation between the longwave and shortwave effects helps to constrain biases in the total cloud effect for most reanalyses. The vertical distribution of cloud water content emerges as a key difference between ERA-Interim and the other reanalyses. Whereas ERA-Interim shows a monotonic decrease of cloud water content with increasing height, the other reanalyses all produce distinct anvil layers. The latter is in better agreement with observations and yields very different profiles of radiative heating in the UTLS. For example, whereas the altitude of the level of zero net radiative heating tends to be lower in convective regions than in the rest of the tropics in ERA-Interim, the opposite is true for the other four reanalyses. Differences in cloud water content also help to explain systematic differences in diabatic ascent in the tropical lower stratosphere among the reanalyses. We discuss several ways in which aspects of the cloud and convection schemes impact the tropical environment. Discrepancies in the vertical profile of moist static energy in convective regions are particularly noteworthy, as this metric is based exclusively on variables that are directly constrained by data assimilation.

scholarly journals Impact of a new emission inventory on CAM5 simulations of aerosols and aerosol radiative effects in eastern China

2016 ◽  
Author(s):  
Tianyi Fan ◽  
Xiaohong Liu ◽  
Po-Lun Ma ◽  
Qiang Zhang ◽  
Zhanqing Li ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Emission Inventory ◽  
Climate Models ◽  
Eastern China ◽  
Radiative Effects ◽  
Surface Cooling ◽  
Climate Effect ◽  
Aerosol Distribution

Abstract. Emissions of aerosols and gas precursors in China have increased significantly over the past three decades with the rapid economic growth. These increases might have a large climate effect. However, global aerosol-climate models often show large biases in aerosol distribution and radiative forcing in China, and these biases are often attributed to uncertainties and biases associated with the emission inventory used to drive the models. In this study, an energy-statics and technology-based emission inventory, Multi-scale Emission Inventory for China (MEIC), was compiled and used to drive the Community Atmosphere Model Version 5 (CAM5) to evaluate aerosol distribution and radiative effects in China against observations, compared with the model simulations with the widely-used IPCC AR5 emission inventory. We found that the new MEIC emission improves the annual mean AOD simulations in eastern China by 12.9 % compared with MODIS observations and 14.7 % compared with MISR observations, and explains 22 %–28 % of the AOD low bias simulated with the AR5 emission. Seasonal variation of the MEIC emission leads to a better agreement with the observed surface concentrations of primary aerosols (i.e., primary organic carbon and black carbon) than the AR5 emission, while the seasonal variation of secondary aerosols (i.e., sulfate and secondary organic aerosol) depends less on the emission. The new emission inventory estimates the annual averaged aerosol direct radiative effect at TOA, surface, and atmosphere to be −0.50, −12.76, and 12.26 W m−2 respectively over eastern China, which are enhanced by −0.19, −2.42, and 2.23 W m−2 compared with the AR5 emission. Due to higher winter BC emission in MEIC, the atmospheric warming effect and the surface cooling of BC are twice as much as those using the AR5 emission. This study highlights the importance of improving the aerosol and gas precursor emissions in modeling the atmospheric aerosols and their radiative effects.

scholarly journals Understanding the Varied Influence of Midlatitude Jet Position on Clouds and Cloud Radiative Effects in Observations and Global Climate Models

2016 ◽  
Vol 29 (24) ◽  
pp. 9005-9025 ◽  
Author(s):  
Kevin M. Grise ◽  
Brian Medeiros
Keyword(s):  
Vertical Velocity ◽  
Climate Models ◽  
Global Climate ◽  
Storm Track ◽  
Cloud Amount ◽  
Global Climate Models ◽  
Radiative Effects ◽  
Velocity Anomalies ◽  
Cooling Effects ◽  
Cloud Radiative Effects

Abstract This study examines the dynamical mechanisms responsible for changes in midlatitude clouds and cloud radiative effects (CRE) that occur in conjunction with meridional shifts in the jet streams over the North Atlantic, North Pacific, and Southern Oceans. When the midlatitude jet shifts poleward, extratropical cyclones and their associated upward vertical velocity anomalies closely follow. As a result, a poleward jet shift contributes to a poleward shift in high-topped storm-track clouds and their associated longwave CRE. However, when the jet shifts poleward, downward vertical velocity anomalies increase equatorward of the jet, contributing to an enhancement of the boundary layer estimated inversion strength (EIS) and an increase in low cloud amount there. Because shortwave CRE depends on the reflection of solar radiation by clouds in all layers, the shortwave cooling effects of midlatitude clouds increase with both upward vertical velocity anomalies and positive EIS anomalies. Over midlatitude oceans where a poleward jet shift contributes to positive EIS anomalies but downward vertical velocity anomalies, the two effects cancel, and net observed changes in shortwave CRE are small. Global climate models generally capture the observed anomalies associated with midlatitude jet shifts. However, there is large intermodel spread in the shortwave CRE anomalies, with a subset of models showing a large shortwave cloud radiative warming over midlatitude oceans with a poleward jet shift. In these models, midlatitude shortwave CRE is sensitive to vertical velocity perturbations, but the observed sensitivity to EIS perturbations is underestimated. Consequently, these models might incorrectly estimate future midlatitude cloud feedbacks in regions where appreciable changes in both vertical velocity and EIS are projected.

scholarly journals Monte Carlo-based subgrid parameterization of vertical velocity and stratiform cloud microphysics in ECHAM5.5-HAM2

2013 ◽  
Vol 13 (15) ◽  
pp. 7551-7565 ◽  
Author(s):  
J. Tonttila ◽  
P. Räisänen ◽  
H. Järvinen
Keyword(s):  
Monte Carlo ◽  
Water Content ◽  
Vertical Velocity ◽  
Cloud Microphysics ◽  
Cloud Water ◽  
Radiative Effects ◽  
Reference Simulation ◽  
Cloud Water Content ◽  
Cloud Radiative Effects ◽  
The Impact

Abstract. A new method for parameterizing the subgrid variations of vertical velocity and cloud droplet number concentration (CDNC) is presented for general circulation models (GCMs). These parameterizations build on top of existing parameterizations that create stochastic subgrid cloud columns inside the GCM grid cells, which can be employed by the Monte Carlo independent column approximation approach for radiative transfer. The new model version adds a description for vertical velocity in individual subgrid columns, which can be used to compute cloud activation and the subgrid distribution of the number of cloud droplets explicitly. Autoconversion is also treated explicitly in the subcolumn space. This provides a consistent way of simulating the cloud radiative effects with two-moment cloud microphysical properties defined at subgrid scale. The primary impact of the new parameterizations is to decrease the CDNC over polluted continents, while over the oceans the impact is smaller. Moreover, the lower CDNC induces a stronger autoconversion of cloud water to rain. The strongest reduction in CDNC and cloud water content over the continental areas promotes weaker shortwave cloud radiative effects (SW CREs) even after retuning the model. However, compared to the reference simulation, a slightly stronger SW CRE is seen e.g. over mid-latitude oceans, where CDNC remains similar to the reference simulation, and the in-cloud liquid water content is slightly increased after retuning the model.

scholarly journals Effects of Cloud Microphysics on the Vertical Structures of Cloud Radiative Effects over the Tibetan Plateau and the Arctic

2021 ◽  
Vol 13 (14) ◽  
pp. 2651
Author(s):  
Yafei Yan ◽  
Yimin Liu ◽  
Xiaolin Liu ◽  
Xiaocong Wang
Keyword(s):  
Tibetan Plateau ◽  
Cloud Microphysics ◽  
Mixed Phase ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
The Tibetan Plateau ◽  
Radiative Effects ◽  
Cloud Radiative Effects ◽  
Phase Water

The Tibetan Plateau (TP) and the Arctic are both cold, fragile, and sensitive to global warming. However, they have very different cloud radiative effects (CRE) and influences on the climate system. In this study, the effects of cloud microphysics on the vertical structures of CRE over the two regions are analyzed and compared by using CloudSat/CALIPSO satellite data and the Rapid Radiative Transfer Model. Results show there is a greater amount of cloud water particles with larger sizes over the TP than over the Arctic, and the supercooled water is found to be more prone to exist over the former than the latter, making shortwave and longwave CRE, as well as the net CRE, much stronger over the TP. Further investigations indicate that the vertical structures of CRE at high altitudes are primarily dominated by cloud ice water, while those at low altitudes are dominated by cloud liquid and mixed-phase water. The liquid and mixed-phase water results in a strong shallow heating (cooling) layer above the cooling (heating) layer in the shortwave (longwave) CRE profiles, respectively.

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