scholarly journals Insights into Earth’s Energy Imbalance from Multiple Sources

2016 ◽  
Vol 29 (20) ◽  
pp. 7495-7505 ◽  
Author(s):  
Kevin E. Trenberth ◽  
John T. Fasullo ◽  
Karina von Schuckmann ◽  
Lijing Cheng
Keyword(s):  
Heat Content ◽  
System Model ◽  
Multiple Sources ◽  
Short Term ◽  
Ocean Reanalysis ◽  
Energy Imbalance ◽  
Community Earth System Model ◽  
Global Estimates ◽  
Standard Deviations ◽  
Radiation Measurements

Abstract The current Earth’s energy imbalance (EEI) can best be estimated from changes in ocean heat content (OHC), complemented by top-of-atmosphere (TOA) radiation measurements and an assessment of the small non-ocean components. Sustained observations from the Argo array of autonomous profiling floats enable near-global estimates of OHC since 2005, which reveal considerable cancellation of variations in the upper 300 m. An analysis of the monthly contributions to EEI from non-ocean components (land and ice) using the Community Earth System Model (CESM) Large Ensemble reveals standard deviations of 0.3–0.4 W m−2 (global); largest values occur in August, but values are below 0.75 W m−2 greater than 95% of the time. Global standard deviations of EEI of 0.64 W m−2 based on top-of-atmosphere observations therefore substantially constrain ocean contributions, given by the tendencies of OHC. Instead, monthly standard deviations of many Argo-based OHC tendencies are 6–13 W m−2, and nonphysical fluctuations are clearly evident. It is shown that an ocean reanalysis with multivariate dynamical data assimilation features much better agreement with TOA radiation, and 44% of the vertically integrated short-term OHC trend for 2005–14 of 0.8 ± 0.2 W m−2 (globally) occurs below 700-m depth. Largest warming occurs from 20° to 50°S, especially over the southern oceans, and near 40°N in all ocean analyses. The EEI is estimated to be 0.9 ± 0.3 W m−2 for 2005–14.

Earth’s Energy Imbalance

2014 ◽  
Vol 27 (9) ◽  
pp. 3129-3144 ◽  
Author(s):  
Kevin E. Trenberth ◽  
John T. Fasullo ◽  
Magdalena A. Balmaseda
Keyword(s):  
Climate Change ◽  
Time Scales ◽  
Radiative Forcing ◽  
Heat Content ◽  
Volcanic Eruptions ◽  
Climate Change Signal ◽  
Ocean Reanalysis ◽  
Climate System Model ◽  
Energy Imbalance ◽  
Rates Of Change

Abstract Climate change from increased greenhouse gases arises from a global energy imbalance at the top of the atmosphere (TOA). TOA measurements of radiation from space can track changes over time but lack absolute accuracy. An inventory of energy storage changes shows that over 90% of the imbalance is manifested as a rise in ocean heat content (OHC). Data from the Ocean Reanalysis System, version 4 (ORAS4), and other OHC-estimated rates of change are used to compare with model-based estimates of TOA energy imbalance [from the Community Climate System Model, version 4 (CCSM4)] and with TOA satellite measurements for the year 2000 onward. Most ocean-only OHC analyses extend to only 700-m depth, have large discrepancies among the rates of change of OHC, and do not resolve interannual variability adequately to capture ENSO and volcanic eruption effects, all aspects that are improved with assimilation of multivariate data. ORAS4 rates of change of OHC quantitatively agree with the radiative forcing estimates of impacts of the three major volcanic eruptions since 1960 (Mt. Agung, 1963; El Chichón, 1982; and Mt. Pinatubo, 1991). The natural variability of the energy imbalance is substantial from month to month, associated with cloud and weather variations, and interannually mainly associated with ENSO, while the sun affects 15% of the climate change signal on decadal time scales. All estimates (OHC and TOA) show that over the past decade the energy imbalance ranges between about 0.5 and 1 W m−2. By using the full-depth ocean, there is a better overall accounting for energy, but discrepancies remain at interannual time scales between OHC- and TOA-based estimates, notably in 2008/09.

scholarly journals Multidecadal preconditioning of the Maud Rise polynya region

Ocean Science ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 1443-1457
Author(s):  
René M. van Westen ◽  
Henk A. Dijkstra
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Large Scale ◽  
Heat Content ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Model Resolution ◽  
Community Earth System Model ◽  
Maud Rise

Abstract. In this paper, we consider Maud Rise polynya formation in a long (250-year) high-resolution (ocean 0.1∘, atmosphere 0.5∘ horizontal model resolution) of the Community Earth System Model. We find a dominant multidecadal timescale in the occurrence of these Maud Rise polynyas. Analysis of the results leads us to the interpretation that a preferred timescale can be induced by the variability of the Weddell Gyre, previously identified as the Southern Ocean Mode. The large-scale pattern of heat content variability associated with the Southern Ocean Mode modifies the stratification in the Maud Rise region and leads to a preferred timescale in convection through preconditioning of the subsurface density and consequently to polynya formation.

scholarly journals Multidecadal Preconditioning of the Maud Rise Polynya Region

2020 ◽  
Author(s):  
René M. van Westen ◽  
Henk A. Dijkstra
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Time Scale ◽  
Large Scale ◽  
Heat Content ◽  
System Model ◽  
Earth System ◽  
Model Resolution ◽  
Community Earth System Model ◽  
Maud Rise

Abstract. In this paper, we consider Maud Rise polynya formation in a long (250 years) high-resolution (ocean 0.1°, atmosphere 0.5° horizontal model resolution) of the Community Earth System Model. We find a dominant multidecadal time scale in the occurrence of these Maud Rise polynyas. Analysis of the results leads us to the interpretation that a preferred time scale can be induced by the variability of the Weddell Gyre, previously identified as the Southern Ocean Mode. The large-scale pattern of heat content variability associated with the Southern Ocean Mode modifies the stratification in the Maud Rise region and leads to a preferred time scale in convection through preconditioning of the subsurface density, and consequently to polynya formation.

An Analysis of The Impact of Short-Term Vacation Rentals on the Hotel Industry

2021 ◽  
pp. 109634802110191
Author(s):  
Jungtae Soh ◽  
Kwanglim Seo
Keyword(s):  
Economic Effect ◽  
Hotel Industry ◽  
Price Difference ◽  
Multiple Sources ◽  
Short Term ◽  
Hotel Performance ◽  
Negative Effect ◽  
Research Gap ◽  
The Impact ◽  
Scholarly Attention

Much scholarly attention has been paid to Airbnb’s influence on the hotel industry. However, extant studies have limitations because they consider only Airbnb while overlooking various other short-term vacation rental players that can also affect performance of hotels. To address this research gap, this study aims to provide a broader understanding of the impacts of short-term vacation rentals by analyzing data obtained from various vacation rental platforms. This study shows that while increase in short-term vacation rentals has an overall negative effect on hotel performance, the economic effect is more significant in the low-end market than in the high-end market. Our findings further reveal that the negative effect is reduced when there is a large price difference between short-term vacation rentals and hotels. By comprehensively examining multiple sources of data on hotels and vacation rentals, this study brings alternative perspectives to the attention of researchers for further investigation of vacation rentals.

scholarly journals 20th century cooling of the deep ocean contributed to delayed acceleration of Earth’s energy imbalance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Bagnell ◽  
T. DeVries
Keyword(s):  
20Th Century ◽  
Heat Content ◽  
Deep Ocean ◽  
Ocean Warming ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Energy Imbalance ◽  
Delayed Onset ◽  
The Past ◽  
Historical Reconstructions

AbstractThe historical evolution of Earth’s energy imbalance can be quantified by changes in the global ocean heat content. However, historical reconstructions of ocean heat content often neglect a large volume of the deep ocean, due to sparse observations of ocean temperatures below 2000 m. Here, we provide a global reconstruction of historical changes in full-depth ocean heat content based on interpolated subsurface temperature data using an autoregressive artificial neural network, providing estimates of total ocean warming for the period 1946-2019. We find that cooling of the deep ocean and a small heat gain in the upper ocean led to no robust trend in global ocean heat content from 1960-1990, implying a roughly balanced Earth energy budget within −0.16 to 0.06 W m−2 over most of the latter half of the 20th century. However, the past three decades have seen a rapid acceleration in ocean warming, with the entire ocean warming from top to bottom at a rate of 0.63 ± 0.13 W m−2. These results suggest a delayed onset of a positive Earth energy imbalance relative to previous estimates, although large uncertainties remain.

scholarly journals Regional Climate Simulations With the Community Earth System Model

2018 ◽  
Vol 10 (6) ◽  
pp. 1245-1265 ◽  
Author(s):  
A. Gettelman ◽  
P. Callaghan ◽  
V. E. Larson ◽  
C. M. Zarzycki ◽  
J. T. Bacmeister ◽  
...  
Keyword(s):  
Regional Climate ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Climate Simulations ◽  
Community Earth System Model

scholarly journals Evaluating simplified chemical mechanisms within present-day simulations of the Community Earth System Model version 1.2 with CAM4 (CESM1.2 CAM-chem): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast chemistry

2018 ◽  
Vol 11 (10) ◽  
pp. 4155-4174 ◽  
Author(s):  
Benjamin Brown-Steiner ◽  
Noelle E. Selin ◽  
Ronald Prinn ◽  
Simone Tilmes ◽  
Louisa Emmons ◽  
...  
Keyword(s):  
Computational Cost ◽  
Earth System Model ◽  
Chemical Mechanism ◽  
System Model ◽  
Earth System ◽  
Chemical Mechanisms ◽  
Trade Offs ◽  
Community Earth System Model ◽  
Time Periods ◽  
Fast Mechanism

Abstract. While state-of-the-art complex chemical mechanisms expand our understanding of atmospheric chemistry, their sheer size and computational requirements often limit simulations to short lengths or ensembles to only a few members. Here we present and compare three 25-year present-day offline simulations with chemical mechanisms of different levels of complexity using the Community Earth System Model (CESM) Version 1.2 CAM-chem (CAM4): the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) mechanism, the Reduced Hydrocarbon mechanism, and the Super-Fast mechanism. We show that, for most regions and time periods, differences in simulated ozone chemistry between these three mechanisms are smaller than the model–observation differences themselves. The MOZART-4 mechanism and the Reduced Hydrocarbon are in close agreement in their representation of ozone throughout the troposphere during all time periods (annual, seasonal, and diurnal). While the Super-Fast mechanism tends to have higher simulated ozone variability and differs from the MOZART-4 mechanism over regions of high biogenic emissions, it is surprisingly capable of simulating ozone adequately given its simplicity. We explore the trade-offs between chemical mechanism complexity and computational cost by identifying regions where the simpler mechanisms are comparable to the MOZART-4 mechanism and regions where they are not. The Super-Fast mechanism is 3 times as fast as the MOZART-4 mechanism, which allows for longer simulations or ensembles with more members that may not be feasible with the MOZART-4 mechanism given limited computational resources.

scholarly journals An Evaluation and Implementation of the Regional Coupled Ice-Ocean Model of the Baltic Sea

2017 ◽  
Author(s):  
Jaromir Jakacki ◽  
Sebastian Meler
Keyword(s):  
Baltic Sea ◽  
Three Dimensional ◽  
Coupled Model ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
System Model ◽  
The Baltic Sea ◽  
Community Earth System Model ◽  
The Baltic ◽  
Ice Model

Abstract. A three dimensional, regional coupled ice-ocean model based on the open-source Community Earth System Model has been developed and implemented for the Baltic Sea. The model consists of 66 vertical levels and has a horizontal resolution of approx. 2.3 km. The paper focuses on sea ice component results but the main changes have been introduced in the ocean part of the coupled model. The hydrodynamic part, being one of the most important components, has been also presented and validated. The ice model results were validated against the radar and satellite data, and the method of validation based on probability was introduced. In the last two decades satellite and model results show an increase in the ice extent over the whole Baltic Sea, which is an evidence of a negative trend in air temperature in recent decades and increasing of winter discharge from the catchment area.

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