scholarly journals Radiative Energy Flux Variation from 2001–2020

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1297
Author(s):  
Hans-Rolf Dübal ◽  
Fritz Vahrenholt
Keyword(s):  
Energy Flux ◽  
Heat Content ◽  
Surface Flux ◽  
Time Frame ◽  
Radiative Flux ◽  
Shortwave Radiation ◽  
Radiative Energy ◽  
Root Cause ◽  
Flux Data ◽  
The North

Radiative energy flux data, downloaded from CERES, are evaluated with respect to their variations from 2001 to 2020. We found the declining outgoing shortwave radiation to be the most important contributor for a positive TOA (top of the atmosphere) net flux of 0.8 W/m2 in this time frame. We compare clear sky with cloudy areas and find that changes in the cloud structure should be the root cause for the shortwave trend. The radiative flux data are compared with ocean heat content data and analyzed in the context of a longer-term climate system enthalpy estimation going back to the year 1750. We also report differences in the trends for the Northern and Southern hemisphere. The radiative data indicate more variability in the North and higher stability in the South. The drop of cloudiness around the millennium by about 1.5% has certainly fostered the positive net radiative flux. The declining TOA SW (out) is the major heating cause (+1.42 W/m2 from 2001 to 2020). It is almost compensated by the growing chilling TOA LW (out) (−1.1 W/m2). This leads together with a reduced incoming solar of −0.17 W/m2 to a small growth of imbalance of 0.15 W/m2. We further present surface flux data which support the strong influence of the cloud cover on the radiative budget.

scholarly journals Have Aerosols Caused the Observed Atlantic Multidecadal Variability?

2013 ◽  
Vol 70 (4) ◽  
pp. 1135-1144 ◽  
Author(s):  
Rong Zhang ◽  
Thomas L. Delworth ◽  
Rowan Sutton ◽  
Daniel L. R. Hodson ◽  
Keith W. Dixon ◽  
...  
Keyword(s):  
Twentieth Century ◽  
North Atlantic ◽  
Heat Content ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Shortwave Radiation ◽  
Multidecadal Variability ◽  
The North ◽  
The North Atlantic ◽  
Aerosol Effects

Abstract Identifying the prime drivers of the twentieth-century multidecadal variability in the Atlantic Ocean is crucial for predicting how the Atlantic will evolve in the coming decades and the resulting broad impacts on weather and precipitation patterns around the globe. Recently, Booth et al. showed that the Hadley Centre Global Environmental Model, version 2, Earth system configuration (HadGEM2-ES) closely reproduces the observed multidecadal variations of area-averaged North Atlantic sea surface temperature in the twentieth century. The multidecadal variations simulated in HadGEM2-ES are primarily driven by aerosol indirect effects that modify net surface shortwave radiation. On the basis of these results, Booth et al. concluded that aerosols are a prime driver of twentieth-century North Atlantic climate variability. However, here it is shown that there are major discrepancies between the HadGEM2-ES simulations and observations in the North Atlantic upper-ocean heat content, in the spatial pattern of multidecadal SST changes within and outside the North Atlantic, and in the subpolar North Atlantic sea surface salinity. These discrepancies may be strongly influenced by, and indeed in large part caused by, aerosol effects. It is also shown that the aerosol effects simulated in HadGEM2-ES cannot account for the observed anticorrelation between detrended multidecadal surface and subsurface temperature variations in the tropical North Atlantic. These discrepancies cast considerable doubt on the claim that aerosol forcing drives the bulk of this multidecadal variability.

scholarly journals Joint Modelling of Wave Energy Flux and Wave Direction

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 460
Author(s):  
Takvor H. Soukissian ◽  
Flora E. Karathanasi
Keyword(s):  
Energy Flux ◽  
Wave Energy ◽  
Goodness Of Fit ◽  
North Atlantic Ocean ◽  
Wave Climate ◽  
Western Mediterranean ◽  
Wave Direction ◽  
Bivariate Model ◽  
The North ◽  
Wave Energy Flux

In the context of wave resource assessment, the description of wave climate is usually confined to significant wave height and energy period. However, the accurate joint description of both linear and directional wave energy characteristics is essential for the proper and detailed optimization of wave energy converters. In this work, the joint probabilistic description of wave energy flux and wave direction is performed and evaluated. Parametric univariate models are implemented for the description of wave energy flux and wave direction. For wave energy flux, conventional, and mixture distributions are examined while for wave direction proven and efficient finite mixtures of von Mises distributions are used. The bivariate modelling is based on the implementation of the Johnson–Wehrly model. The examined models are applied on long-term measured wave data at three offshore locations in Greece and hindcast numerical wave model data at three locations in the western Mediterranean, the North Sea, and the North Atlantic Ocean. A global criterion that combines five individual goodness-of-fit criteria into a single expression is used to evaluate the performance of bivariate models. From the optimum bivariate model, the expected wave energy flux as function of wave direction and the distribution of wave energy flux for the mean and most probable wave directions are also obtained.

scholarly journals The North Sulawesi Seas Water Masses Heat Content in 1995 – 2015

2020 ◽  
Vol 618 ◽  
pp. 012015
Author(s):  
Fauzan L Ramadhan ◽  
Luqman N Chairuasni ◽  
Lamona I Bernawis ◽  
Rima Rachmayani ◽  
Mutiara R Putri
Keyword(s):  
Heat Content ◽  
Water Masses ◽  
The North ◽  
North Sulawesi

The Role of Oceanic Heat Advection in the Evolution of Tropical North and South Atlantic SST Anomalies*

2006 ◽  
Vol 19 (23) ◽  
pp. 6122-6138 ◽  
Author(s):  
Gregory R. Foltz ◽  
Michael J. McPhaden
Keyword(s):  
Surface Flux ◽  
South Atlantic ◽  
Shortwave Radiation ◽  
Heat Advection ◽  
Horizontal Advection ◽  
Latent Heat Loss ◽  
North And South ◽  
Sst Gradient ◽  
Sst Anomalies

Abstract The role of horizontal oceanic heat advection in the generation of tropical North and South Atlantic sea surface temperature (SST) anomalies is investigated through an analysis of the oceanic mixed layer heat balance. It is found that SST anomalies poleward of 10° are driven primarily by a combination of wind-induced latent heat loss and shortwave radiation. Away from the eastern boundary, horizontal advection damps surface flux–forced SST anomalies due to a combination of mean meridional Ekman currents acting on anomalous meridional SST gradients, and anomalous meridional currents acting on the mean meridional SST gradient. Horizontal advection is likely to have the most significant effect on the interhemispheric SST gradient mode through its impact in the 10°–20° latitude bands of each hemisphere, where the variability in advection is strongest and its negative correlation with the surface heat flux is highest. In addition to the damping effect of horizontal advection in these latitude bands, evidence for coupled wind–SST feedbacks is found, with anomalous equatorward (poleward) SST gradients contributing to enhanced (reduced) westward surface winds and an equatorward propagation of SST anomalies.

scholarly journals Comparison of Radiative Energy Flows in Observational Datasets and Climate Modeling

2016 ◽  
Vol 55 (1) ◽  
pp. 93-117 ◽  
Author(s):  
Ehrhard Raschke ◽  
Stefan Kinne ◽  
William B. Rossow ◽  
Paul W. Stackhouse ◽  
Martin Wild
Keyword(s):  
Climate Modeling ◽  
Radiative Flux ◽  
Radiative Energy ◽  
Trade Wind ◽  
Radiative Effects ◽  
Ancillary Data ◽  
Global Modeling ◽  
Lower Altitude ◽  
Clear Sky ◽  
Cloud Radiative Effects

AbstractThis study examines radiative flux distributions and local spread of values from three major observational datasets (CERES, ISCCP, and SRB) and compares them with results from climate modeling (CMIP3). Examinations of the spread and differences also differentiate among contributions from cloudy and clear-sky conditions. The spread among observational datasets is in large part caused by noncloud ancillary data. Average differences of at least 10 W m−2 each for clear-sky downward solar, upward solar, and upward infrared fluxes at the surface demonstrate via spatial difference patterns major differences in assumptions for atmospheric aerosol, solar surface albedo and surface temperature, and/or emittance in observational datasets. At the top of the atmosphere (TOA), observational datasets are less influenced by the ancillary data errors than at the surface. Comparisons of spatial radiative flux distributions at the TOA between observations and climate modeling indicate large deficiencies in the strength and distribution of model-simulated cloud radiative effects. Differences are largest for lower-altitude clouds over low-latitude oceans. Global modeling simulates stronger cloud radiative effects (CRE) by +30 W m−2 over trade wind cumulus regions, yet smaller CRE by about −30 W m−2 over (smaller in area) stratocumulus regions. At the surface, climate modeling simulates on average about 15 W m−2 smaller radiative net flux imbalances, as if climate modeling underestimates latent heat release (and precipitation). Relative to observational datasets, simulated surface net fluxes are particularly lower over oceanic trade wind regions (where global modeling tends to overestimate the radiative impact of clouds). Still, with the uncertainty in noncloud ancillary data, observational data do not establish a reliable reference.

Disaster Metrics: Quantitative Estimation of the Number of Ambulances Required in Trauma-Related Multiple Casualty Events

2012 ◽  
Vol 27 (5) ◽  
pp. 445-451 ◽  
Author(s):  
Jamil D. Bayram ◽  
Shawki Zuabi ◽  
Mazen J. El Sayed
Keyword(s):  
Quantitative Estimation ◽  
The United States ◽  
Time Frame ◽  
Quantitative Model ◽  
Time Interval ◽  
Publication Type ◽  
The North ◽  
Number Of Patients ◽  
Minimum Number ◽  
T1 And T2

AbstractIntroductionEstimating the number of ambulances needed in trauma-related Multiple Casualty Events (MCEs) is a challenging task.Hypothesis/ProblemEmergency medical services (EMS) regions in the United States have varying “best practices” for the required number of ambulances in MCE, none of which is based on metric criteria. The objective of this study was to estimate the number of ambulances required to respond to the scene of trauma-related MCE in order to initiate treatment and complete the transport of critical (T1) and moderate (T2) patients. The proposed model takes into consideration the different transport times and capacities of receiving hospitals, the time interval from injury occurrence, the number of patients per ambulance, and the pre-designated time frame allowed from injury until the transfer care of T1 and T2 patients.MethodsThe main theoretical framework for this model was based on prehospital time intervals described in the literature and used by EMS systems to evaluate operational and patient care issues. The North Atlantic Treaty Organization (NATO) triage categories (T1-T4) were used for simplicity.ResultsThe minimum number of ambulances required to respond to the scene of an MCE was modeled as being primarily dependent on the number of critical patients (T1) present at the scene any particular time. A robust quantitative model was also proposed to dynamically estimate the number of ambulances needed at any time during an MCE to treat, transport and transfer the care of T1 and T2 patients.ConclusionA new quantitative model for estimation of the number of ambulances needed during the prehospital response in trauma-related multiple casualty events has been proposed. Prospective studies of this model are needed to examine its validity and applicability.BayramJD, ZuabiS, El SayedMJ. Disaster metrics: quantitative estimation of the number of ambulances required in trauma-related multiple casualty events. Prehosp Disaster Med.2012;27(5):1-7.

scholarly journals Impact of the Desert dust on the summer monsoon system over Southwestern North America

2012 ◽  
Vol 12 (8) ◽  
pp. 3717-3731 ◽  
Author(s):  
C. Zhao ◽  
X. Liu ◽  
L. R. Leung
Keyword(s):  
North America ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Lower Atmosphere ◽  
Shortwave Radiation ◽  
Western Slope ◽  
Monsoon Circulation ◽  
The North ◽  
Moisture Fluxes ◽  
June July

Abstract. The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995–2009). During the monsoon season, dust has a cooling effect (−0.90 W m−2) at the surface, a warming effect (0.40 W m−2) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (−0.50 W m−2) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day−1 over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to ~40 % over the eastern slope of the Mountains (Arizona-New~Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the mega-drought conditions projected for the future.

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