An evaluation of the schemes of ocean surface albedo parameterization in shortwave radiation estimation

Abstract. Ocean surface represents roughly 70 % of the Earth's surface, playing a large role in the partitioning of the energy flow within the climate system. The ocean surface albedo (OSA) is an important parameter in this partitioning because it governs the amount of energy penetrating into the ocean or reflected towards space. The old OSA schemes in the ARPEGE-Climat and LMDZ models only resolve the latitudinal dependence in an ad hoc way without an accurate representation of the solar zenith angle dependence. Here, we propose a new interactive OSA scheme suited for Earth system models, which enables coupling between Earth system model components like surface ocean waves and marine biogeochemistry. This scheme resolves spectrally the various contributions of the surface for direct and diffuse solar radiation. The implementation of this scheme in two Earth system models leads to substantial improvements in simulated OSA. At the local scale, models using the interactive OSA scheme better replicate the day-to-day distribution of OSA derived from ground-based observations in contrast to old schemes. At global scale, the improved representation of OSA for diffuse radiation reduces model biases by up to 80 % over the tropical oceans, reducing annual-mean model–data error in surface upwelling shortwave radiation by up to 7 W m−2 over this domain. The spatial correlation coefficient between modeled and observed OSA at monthly resolution has been increased from 0.1 to 0.8. Despite its complexity, this interactive OSA scheme is computationally efficient for enabling precise OSA calculation without penalizing the elapsed model time.

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An interactive ocean surface albedo scheme: formulation and evaluation in two atmospheric models

10.5194/gmd-2017-111 ◽

2017 ◽

Cited By ~ 2

Author(s):

Roland Séférian ◽

Sunghye Baek ◽

Olivier Boucher ◽

Jean-Louis Dufresne ◽

Bertrand Decharme ◽

...

Keyword(s):

Surface Albedo ◽

Ad Hoc ◽

Diffuse Radiation ◽

Ocean Surface ◽

Global Scale ◽

Shortwave Radiation ◽

Earth System ◽

Diffuse Solar Radiation ◽

System Models ◽

Earth System Models

Abstract. Ocean surface represents roughly 70 % of the Earth surface, playing a large role in the partitioning of the energy flow within the climate system. The ocean surface albedo (OSA) is an important parameter in this partitioning because it governs the amount of energy penetrating into the ocean or reflected towards space. The old OSA schemes in the ARPEGE and LMDZ models only resolve the latitudinal dependence in an ad hoc way without an accurate representation of the solar zenith angle dependence. Here, we propose a new interactive OSA scheme suited for Earth system models, which gather contributions for relevant OSA processes published in the literature over the last decades. This scheme resolves spectrally the various contributions of the surface for direct and diffuse solar radiation. The implementation of this scheme in two Earth system models leads to substantial improvements in simulated OSA. At the local scale, models using the interactive OSA scheme better replicate the day-to-day distribution of OSA derived from ground-based observations in contrast to old schemes. At global scale, the improved representation of OSA for diffuse radiation reduces model biases by up to 80 % over the tropical oceans, reducing annual-mean model-data error in surface upwelling shortwave radiation by up to 7 W m−2 over this domain. The spatial correlation coefficient between modelled and observed OSA at monthly resolution has been increased from 0.1 to 0.8. Despite its complexity, this interactive OSA scheme is computationally efficient to enable precise OSA calculation without penalizing the model elapsed time.

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Supplementary material to "An interactive ocean surface albedo scheme: formulation and evaluation in two atmospheric models"

10.5194/gmd-2017-111-supplement ◽

2017 ◽

Author(s):

Roland Séférian ◽

Sunghye Baek ◽

Olivier Boucher ◽

Jean-Louis Dufresne ◽

Bertrand Decharme ◽

...

Keyword(s):

Surface Albedo ◽

Ocean Surface ◽

Atmospheric Models ◽

Supplementary Material

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Characterization of Canadian High Arctic glacier surface albedo from MODIS C6 data, 2001–2016

10.5194/tc-2017-160 ◽

2017 ◽

Author(s):

Colleen A. Mortimer ◽

Martin Sharp

Keyword(s):

Large Scale ◽

Surface Albedo ◽

Temporal Trends ◽

Principal Component ◽

High Arctic ◽

Shortwave Radiation ◽

Glacier Surface ◽

Annual Variations ◽

The Mean ◽

Moderate Resolution Imaging Spectroradiometer

Abstract. Inter-annual variations and longer-term trends in the annual mass balance of glaciers in Canada's Queen Elizabeth Islands (QEI) are largely attributable to changes in summer melt. The largest source of melt energy in the QEI in summer is net shortwave radiation, which is modulated by changes in glacier surface albedo. We used measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to investigate large scale spatial patterns and temporal trends and variability in the summer surface albedo of QEI glaciers and their relationship to observed changes in glacier surface temperature from 2001 to 2016. Mean summer black-sky shortwave broadband albedo (BSA) decreased at a rate of 0.029 ± 0.025 decade-1 over that period. Larger reductions in BSA occurred in July (−0.050 ± 0.031 decade-1). No change in BSA was observed in either June or August. Most of the decrease in BSA, which was greatest at lower elevations around the margins of the ice masses, occurred between 2007 and 2012 when mean summer BSA was anomalously low. The First Principal Component of the 16-year record of mean summer BSA was well correlated with the mean summer North Atlantic Oscillation Index, except in 2006, 2010, and 2016. During this 16-year period, the mean summer LST increased by 0.046 ± 0.036 °C yr-1 and the BSA record was negatively correlated (−0.64, p

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Cloudiness and Earth's hemispheric albedo symmetry

10.5194/egusphere-egu21-153 ◽

2021 ◽

Author(s):

George Datseris ◽

Bjorn Stevens

Keyword(s):

Surface Albedo ◽

Shortwave Radiation ◽

Cloud Albedo ◽

Radiation Data ◽

Cloud Properties ◽

Open Questions ◽

Long Time ◽

Planetary Albedo ◽

Hemispheric Communication ◽

Radiation Measurements

<p>Radiation measurements at the top of the atmosphere show that the two hemispheres of Earth reflect the same amount of shortwave radiation in the long time average (so-called hemispheric albedo symmetry). Here we try to find the origin of this symmetry by analyzing radiation data directly, as well as cloud properties. The radiation data, while being mostly noise, hint that a hemispheric communication mechanism is likely but do not provide enough information to identify it. Cloud properties allow us to define an effective cloud albedo field, much more useful than the commonly used cloud area fraction. Based on that we first show that extra cloud albedo of the SH exactly compensates the extra surface albedo of the NH. We then identify that this this compensation comes almost exclusively from the storm tracks of the extratropics. We close discussing the importance of approaching planetary albedo as a whole and open questions that remain.</p>

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Spatiotemporal distributions of 0.4-14 μm ocean surface albedo over China Sea areas

Infrared and Laser Engineering ◽

10.3788/irla201847.1212001 ◽

2018 ◽

Vol 47 (12) ◽

pp. 1212001

Author(s):

崔生成 Cui Shengcheng ◽

朱文越 Zhu Wenyue ◽

李学彬 Li Xuebin ◽

罗涛 Luo Tao ◽

张梓晗 Zhang Zihan ◽

...

Keyword(s):

Surface Albedo ◽

Ocean Surface ◽

China Sea ◽

Spatiotemporal Distributions

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Spring Arctic Atmospheric Preconditioning: Do Not Rule Out Shortwave Radiation Just Yet

Journal of Climate ◽

10.1175/jcli-d-17-0710.1 ◽

2018 ◽

Vol 31 (11) ◽

pp. 4225-4240 ◽

Cited By ~ 3

Author(s):

Joseph Sedlar

Keyword(s):

Sea Ice ◽

Surface Albedo ◽

Atmospheric Transport ◽

High Surface ◽

Longwave Radiation ◽

Absolute Magnitude ◽

Arctic Sea Ice ◽

Shortwave Radiation ◽

The Arctic ◽

Ice Melt

Abstract Springtime atmospheric preconditioning of Arctic sea ice for enhanced or buffered sea ice melt during the subsequent melt year has received considerable research focus. Studies have identified enhanced poleward atmospheric transport of moisture and heat during spring, leading to increased emission of longwave radiation to the surface. Simultaneously, these studies ruled out the role of shortwave radiation as an effective preconditioning mechanism because of relatively weak incident solar radiation, high surface albedo from sea ice and snow, and increased clouds during spring. These conclusions are derived primarily from atmospheric reanalysis, which may not always accurately represent the Arctic climate system. Here, top-of-atmosphere shortwave radiation observations from a state-of-the-art satellite sensor are compared with ERA-Interim reanalysis to examine similarities and differences in the springtime absorbed shortwave radiation (ASR) over the Arctic Ocean. Distinct biases in regional location and absolute magnitude of ASR anomalies are found between satellite-based measurements and reanalysis. Observations indicate separability between ASR anomalies in spring corresponding to anomalously low and high ice extents in September; the reanalysis fails to capture the full extent of this separability. The causes for the difference in ASR anomalies between observations and reanalysis are considered in terms of the variability in surface albedo and cloud presence. Additionally, biases in reanalysis cloud water during spring are presented and are considered for their impact on overestimating spring downwelling longwave anomalies. Taken together, shortwave radiation should not be overlooked as a contributing mechanism to springtime Arctic atmospheric preconditioning.

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Impact of stratospheric aerosol intervention geoengineering on surface air temperature in China: A surface energy budget perspective

10.5194/acp-2021-503 ◽

2021 ◽

Author(s):

Zhaochen Liu ◽

Xianmei Lang ◽

Dabang Jiang

Keyword(s):

Spatial Pattern ◽

Air Temperature ◽

Land Surface ◽

Surface Albedo ◽

Surface Air Temperature ◽

Stratospheric Aerosol ◽

Surface Energy Budget ◽

Shortwave Radiation ◽

Surface Cooling ◽

Temperature Changes

Abstract. Stratospheric aerosol intervention (SAI) geoengineering is a rapid, effective, and promising means to counteract anthropogenic global warming, but the climate response to SAI, with great regional disparities, remains uncertain. In this study, we use Geoengineering Model Intercomparison Project G4 experiment simulations from three models (HadGEM2-ES, MIROC-ESM, and MIROC-ESM-CHEM) that offset anthropogenic forcing under medium-low emissions (RCP4.5) by injecting a certain amount of SO2 into the stratosphere every year, to investigate the surface air temperature response to SAI geoengineering over China. It has been shown that the SAI leads to surface cooling over China over the last 40 years of injection simulation (2030–2069), which varies among models, regions and seasons. The spatial pattern of SAI-induced temperature changes over China is mainly due to net surface shortwave radiation changes. We find that changes in solar radiation modification strength, surface albedo, atmospheric water vapor and cloudiness affect surface shortwave radiation. In summer, the increased cloud cover in some regions reduces net surface shortwave radiation, causing strong surface cooling. In winter, both the strong cooling in all three models and the abnormal warming in MIROC-ESM are related to surface albedo changes. Our results suggest that cloud and land surface processes in models may dominate the spatial pattern of SAI-induced surface air temperature changes over China.

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Surface Energy Balance Sensitivity to Meteorological Variability on Haig Glacier, Canadian Rocky Mountains

10.5194/tc-2016-6 ◽

2016 ◽

Author(s):

S. Ebrahimi ◽

S. J. Marshall

Keyword(s):

Energy Balance ◽

Surface Energy ◽

Rocky Mountains ◽

Surface Albedo ◽

Surface Energy Balance ◽

Specific Humidity ◽

Shortwave Radiation ◽

Interannual Variations ◽

Canadian Rocky Mountains ◽

Glacier Surface

Abstract. Energy exchanges between the atmosphere and the glacier surface control the net energy available for snow and ice melt. Meteorological and glaciological observations are not always available to measure glacier energy and mass balance directly, so models of energy balance processes are often necessary to understand glacier response to meteorological variability and climate change. This paper explores the theoretical and empirical response of a mid-latitude glacier in the Canadian Rocky Mountains to the daily and interannual variations in the meteorological parameters that govern the surface energy balance. The model's reference conditions are based on 11 years of in situ observations from an automatic weather station at an elevation of 2660 m, in the upper ablation area of Haig Glacier. We use an energy balance model to run sensitivity tests to perturbations in temperature, specific humidity, wind speed, incoming shortwave radiation, and glacier surface albedo. The variables were perturbed one at a time for the duration of the glacier melt season, May to September, for the years 2002–2012. The experiments indicate that summer melt has the strongest sensitivity to interannual variations in incoming shortwave radiation, albedo, and temperature, in that order. To explore more realistic scenarios where meteorological variables and internal feedbacks such as the surface albedo co-evolve, we use the same perturbation approach using meteorological forcing from the North American Regional Reanalysis (NARR) over the period 1979–2014. These experiments provide an estimate of historical variability in Haig Glacier surface energy balance an d melt for years prior to our observational study. The methods introduced in this paper provide a methodology that can be employed in distributed energy balance modelling at regional scales. They also provide the foundation for theoretical framework that can be adapted to compare the climatic sensitivity of glaciers in different climate regimes, e.g., polar, maritime, or tropical environments.

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Observations for Model Intercomparison Project (Obs4MIPs): Status for CMIP6

10.5194/gmd-2019-268 ◽

2019 ◽

Cited By ~ 1

Author(s):

Duane Waliser ◽

Peter J. Gleckler ◽

Robert Ferraro ◽

Karl E. Taylor ◽

Sasha Ames ◽

...

Keyword(s):

Model Evaluation ◽

Climate Model ◽

Surface Wind ◽

Ocean Surface ◽

Shortwave Radiation ◽

Model Output ◽

Earth System ◽

Model Intercomparison ◽

Wide Range ◽

Intercomparison Project

Abstract. The Observations for Model Intercomparison Projects (Obs4MIPs) was initiated in 2010 to facilitate the use of observations in climate model evaluation and research, with a particular target being the Coupled Model Intercomparison Project (CMIP), a major initiative of the World Climate Research Programme (WCRP). To this end, Obs4MIPs: 1) targets observed variables that can be compared to CMIP model variables, 2) utilizes dataset formatting specifications and metadata requirements closely aligned with CMIP model output, 3) provides brief technical documentation for each dataset, designed for non-experts and tailored towards relevance for model evaluation, including information on uncertainty, dataset merits and limitations, and 4) disseminates the data through the Earth System Grid Federation (ESGF) platforms, making the observations searchable and accessible via the same portals as the model output. Taken together, these characteristics of the organization and structure of obs4MIPs should entice a more diverse community of researchers to engage in the comparison of model output with observations and to contribute to a more comprehensive evaluation of the climate models. At present, the number of obs4MIPs datasets has grown to about 80, many undergoing updates, with another 20 or so in preparation, and more than 100 proposed and under consideration. Current global satellite-based datasets include, but are not limited to, humidity and temperature profiles; a wide range of cloud and aerosol observations; ocean surface wind, temperature, height, and sea ice fraction; surface and top of atmosphere longwave and shortwave radiation; along with ozone (O3), methane (CH4) and carbon dioxide (CO2) products. Proposed products expected for inclusion for CMIP6 analysis include, but are not limited to, alternative products for the above quantities, along with additional products for ocean surface flux and chlorophyll products, a number of vegetation products (e.g. FAPAR, LAI, burnt area fraction), ice sheet mass and height, carbon monoxide (CO) and nitrogen dioxide (NO2). While most obs4MIPs datasets are delivered as monthly and global, greater emphasis is being places on products with higher time resolution (e.g. daily) and/or regional products. Along with an increasing number of datasets, obs4MIPs has implemented a number of capability upgrades including: 1) an updated obs4MIPs data specifications document that provides for additional search facets and generally improves congruence with CMIP6 specifications for model datasets, 2) a set of six easily understood indicators that help guide users as to a dataset’s maturity and suitability for application, and 3) an option to supply supplemental information about a dataset beyond what can be found in the standard metadata. With the maturation of the obs4MIPs framework, the dataset inclusion process, and the dataset formatting guidelines and resources, the scope of the observations being considered is expected to grow to include gridded in-situ datasets as well as datasets with a regional focus, and the ultimate intent is to judiciously expand this scope to any observation dataset that has applicability for evaluation of the types of Earth System models used in CMIP.

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