Changes In Radiation Balance Research Articles

Study of marine waters hydrological characteristics near the Zmiinyi Island in 2016-2017

Purpose. Results of hydrological characteristics observations in the Zmiinyi Island coastal waters carried out by research group of the Regional Center for Integrated Monitoring and Environmental Studies (Odessa National I.I. Mechnikov University) in 2016-2017 have been summarized. Methods. Primary data on transparency, temperature and salinity of marine water have been collected using standard methods. Data processing, calculation of statistics, producing of graphs and maps have been carried out using Excel and ArcGIS software. Results. Temporal and spatial distributions of transparency, temperature and salinity of marine waters near the Zmiinyi Island for the period from April 2016 to December 2017 have been presented and analyzed. Using the results of analysis of the accumulated experimental data on transparency, temperature and salinity of sea water the peculiarities of those characteristics’ seasonal changes have been revealed. Conclusions. Impact of desalinated water masses advection from the Danube River mouth and from the North Western part of the Black Sea has been revealed. Well-visible seasonal variation was revealed in the sea water temperatures distribution near the Zmiinyi Island in 2016-2017, which reflected seasonal changes in radiation balance and heat exchange processes at the sea / atmosphere boundary, as well as the influence of water masses advection from other areas of the sea. It was shown that salinity seasonal variation in the sea water near the Zmiinyi Island, which ranged from 7.48 to 18.34 PSU, in 2016-2017 had the disturbance as the result of migration of the frontal zone of the Danube River waters distribution in the Zmiinyi Island area, as well as advection of desalinated water masses from the NWBS. Forming of stable two-layer vertical density stratification of the Zmiinyi Island coastal waters in spring-summer periods of 2016-2017 has been traced. An earlier (compared to Odessa Bay) spring vertical thermal stratification of water (May) and smoother, till late autumn, seasonal temperature decrease were revealed.

Regional Responses to Black Carbon Aerosols: The Importance of Air‐Sea Interaction

AbstractThe impact of modern black carbon aerosols on climate via their changes in radiative balance is studied using a coupled model where sea surface temperatures (SSTs) are allowed to vary and an atmosphere‐only version of the same model where SSTs are held fixed. Allowing the ocean to respond is shown to have a profound impact on the pattern of temperature change. Particularly, large impacts are found in the North Pacific (which cools by up to 1 K in the coupled model) and in north central Asia (which warms in the coupled simulation and cools in the fixed SST simulation). Neither set of experiments shows large changes in surface temperatures in the Southeast Asian region where the atmospheric burden of black carbon is highest. These results are related to the stabilization of the atmosphere and changes in oceanic heat transport. Over the North Pacific, atmospheric stabilization results in an increase in stratiform clouds. The resulting shading reduces evaporation, freshening the surface layer of the ocean and reducing the inflow of warm subtropical waters. Over the land, a delicate balance between greater atmospheric absorption, shading of the surface and changes in latent cooling of the surface helps to determine whether warming or cooling is seen. Our results emphasize the importance of coupling in determining the response of the climate system to black carbon and suggest that black carbon may play an important role in modulating climate change over the North Pacific.

Calculation of pitwall sloughing dynamics in carbonate rocks with different freeze resistance

The article proposes mathematical model of heat exchange between open pitwall rocks and atmosphere for forecasting temperature field in permafrost strata, daily change in radiative balance, slope angle and surface orientation, and influence of contiguous benches. In terms of Udachny Open Pit Mine, time dependence of pitwall sloughing layer thickness is estimated under cyclic effect of freezing-defrostation in rocks having different freeze resistance.

Multi-decadal variation of the net downward shortwave radiation over south Asia: The solar dimming effect

The solar radiation flux at the earth's surface has gone through decadal changes of decreasing and increasing trends over the globe. These phenomena known as dimming and brightening, respectively, have attracted the scientific interest in relation to the changes in radiative balance and climate. Despite the interest in the solar dimming/brightening phenomenon in various parts of the world, south Asia has not attracted great scientific attention so far. The present work uses the net downward shortwave radiation (NDSWR) values derived from satellites (Modern Era Retrospective-analysis for Research and Applications, MERRA 2D) in order to examine the multi-decadal variations in the incoming solar radiation over south Asia for the period of 1979-2004. From the analysis it is seen that solar dimming continues over south Asia with a trend of -0.54 Wm(-2) yr(-1). Assuming clear skies an average decrease of -0.05 Wm(-2)yr(-1) in NDSWR was observed, which is attributed to increased aerosol emissions over the region. There is evidence that the increase in cloud optical depth plays the major role for the solar dimming over the area. The cloud optical depth (MERRA retrievals) has increased by 10.7% during the study period, with the largest increase to be detected for the high-level (atmospheric pressure P < 400 hPa) clouds (31.2%). Nevertheless, the decrease in solar radiation and the role of aerosols and clouds exhibit large monthly and seasonal variations directly affected by the local monsoon system, the anthropogenic and natural aerosol emissions. All these aspects are examined in detail aiming at shedding light into the solar dimming phenomenon over a densely populated area. (C) 2011 Elsevier Ltd. All rights reserved.

The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic

Abstract. Understanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent change in radiative balance is examined. A set of idealized climate model simulations were performed to quantify the radiative effects of changes in sea salt aerosol emissions induced by prescribed changes in sea ice extent. The model was forced using sea ice concentrations consistent with present day conditions and projections of sea ice extent for 2100. Sea salt aerosol emissions increase in response to a decrease in sea ice, the model results showing an annual average increase in number emission over the polar cap (70–90° N) of 86 × 106 m−2 s−1 (mass emission increase of 23 μg m−2 s−1). This in turn leads to an increase in the natural aerosol optical depth of approximately 23%. In response to changes in aerosol optical depth, the natural component of the aerosol direct forcing over the Arctic polar cap is estimated to be between −0.2 and −0.4 W m−2 for the summer months, which results in a negative feedback on the system. The model predicts that the change in first indirect aerosol effect (cloud albedo effect) is approximately a factor of ten greater than the change in direct aerosol forcing although this result is highly uncertain due to the crude representation of Arctic clouds and aerosol-cloud interactions in the model. This study shows that both the natural aerosol direct and first indirect effects are strongly dependent on the surface albedo, highlighting the strong coupling between sea ice, aerosols, Arctic clouds and their radiative effects.

The importance of the geophysical context in statistical evaluations of climate reconstruction procedures

A portion of the debate about climate reconstructions of the past millennium, and in particular about the well-known Mann-Bradley-Hughes (“MBH” 1998, 1999) reconstructions, has become disconnected from the goal of understanding natural climate variability. Here, we reflect on what can be learned from recent scientific exchanges and identify important challenges that remain to be addressed openly and productively by the community. One challenge arises from the real, underlying trend in temperatures during the instrumental period. This trend can affect regression-based reconstruction performance in cases where the calibration period does not appropriately cover the range of conditions encountered during the reconstruction. However, because it is tied to a unique spatial pattern driven by change in radiative balance, the trend cannot simply be removed in the method of climate field reconstruction used by MBH on the statistical argument of preserving degrees of freedom. More appropriately, the influence from the trend can be taken into account in some methods of significance testing. We illustrate these considerations as they apply to the MBH reconstruction and show that it remains robust back to AD 1450, and given other empirical information also back to AD 1000. However, there is now a need to move beyond hemispheric average temperatures and to focus instead on resolving climate variability at the socially more relevant regional scale.

The physical mechanism of the solar variability influence on electrical and climatic characteristics of the troposphere

Possible mechanisms of solar–climatic connections, which may be of importance over short and long time intervals, are discussed. The variations of energetic balance of Earth’s climatic system for the last 50 years are estimated. It is ascertained that the imbalance between the flux of solar energy that comes to the Earth and radiates to space is of 0.1% for the last ten years. The significance is analyzed for the possible influence of variations of solar constant upon the energetic balance of the atmosphere. The physical mechanism of the influence of solar activity on climatic characteristics and the atmospheric circulation is suggested and theoretically substantiated. The mechanism is based on the redistribution in lower-troposphere of condensation nuclei by the vertical electric field. This electric field is determined by the ionosphere–Earth electric potential, which in the Polar Regions is controlled not only by tropical thunderstorms and by the galactic cosmic-ray intensity but also by solar cosmic-ray fluxes. The height redistribution in the atmosphere of condensation nuclei with a change of the electric field of the atmosphere is accompanied by a change in total latent heat (phase transition of water vapor), by changes in radiation balance, and by subsequent changes of the thermobaric field of troposphere. The results of analysis of thermobaric field variations for the periods of invasion of abnormally powerful solar cosmic ray fluxes and magnetic storms confirm the reality of manifestation of heliogeophysical disturbances.

Maximum and minimum temperatures: a backward and a forward look

The effects of changing exposure of thermometers at land stations are reviewed, and the documented influences of instrumental changes in the late ninteenth and early twentieth century are presented, as well as some more recent cases. In general, the effect of improved thermometer exposure has been an apparent reduction in the diurnal temperature range, of several tenths °C. Careful intercomparisons, lasting several years, are therefore needed between present and proposed future instrumentation, if further artificial changes are to be avoided. Past data should be carefully compensated for changes of instrumentation and observing practices. The analysis of monthly mean maximum and minimum temperatures is an insufficient basis for an understanding of current changes in diurnal range. Concomitant changes of cloudiness and wind strength should be analysed. Ideally, daily data should be stratified by cloud amount and wind strength so that radiative and advective influences can be assessed. Changes in diurnal range in calm, cloudless conditions may indicate changes in radiative balance owing to greenhouse gases and aerosols.

Response of a stochastically-perturbed 1-D surface energy balance model to increased temperature

The response of the climatic system to changes in its radiative forcing has been the subject of much study. Climate models of various complexity have been used to demonstrate that a small increase in the solar constant, or doubling of the atmospheric CO2, would lead to a warmer surface. Very little scientific attention, however, has been given to the effect such a change in radiative balance might have on climatic variability. That is, would an earth warmed in this way be more temperate or more variable? To move one step closer to answering this question, we employed a simple one-dimensional surface energy balance climate model and forced it with random Gaussian white noise to simulate interannual variability. We integrated the model using 0, 2, and 4% increases in the solar constant. The results of these numerical experiments indicate that, under a warmer surface radiative balance, interannual variability of the surface temperature is reduced.