The Characteristics of Radiation Balance Components During Qxpmex in 1979

The nucleation of ice is vital in cloud physics and impacts on a broad range of matters from the cryopreservation of food, tissues, organs, and stem cells to the prevention of icing on aircraft wings, bridge cables, wind turbines, and other structures. Ice nucleation thus has broad implications in medicine, food engineering, mineralogy, biology, and other fields. Nowadays, the growing threat of global warming has led to intense research activities on the feasibility of artificially modifying clouds to shift the Earth’s radiation balance. For these reasons, nucleation of ice has been extensively studied over many decades and rightfully so. It is thus not quite possible to cover the whole subject of ice nucleation in a single review. Rather, this feature article provides a brief overview of ice nucleation that focuses on several major outstanding fundamental issues. The author’s wish is to aid early researchers in ice nucleation and those who wish to get into the field of ice nucleation from other disciplines by concisely summarizing the outstanding issues in this important field. Two unresolved challenges stood out from the review, namely the lack of a molecular-level picture of ice nucleation at an interface and the limitations of classical nucleation theory.

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Urban radiation balance of two coastal cities in a hot and dry environment

International Journal of Remote Sensing ◽

10.1080/01431160600993389 ◽

2007 ◽

Vol 28 (12) ◽

pp. 2695-2712 ◽

Cited By ~ 29

Author(s):

C. M. Frey ◽

G. Rigo ◽

E. Parlow

Keyword(s):

Radiation Balance ◽

Coastal Cities

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Components of the energy balance of the ground surface and their effect on the thermics of the substrata of the vegetation oasis at Henryk Arctowski Station, King George Island, South Shetland Islands

Polar Record ◽

10.1017/s003224740001593x ◽

2000 ◽

Vol 36 (196) ◽

pp. 3-18 ◽

Cited By ~ 1

Author(s):

P. Prosek ◽

M. Janouch ◽

K. Láska

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Soil Temperature ◽

Sensible Heat Flux ◽

Ground Surface ◽

South Shetland Islands ◽

Radiation Balance ◽

Sensible Heat ◽

King George Island ◽

Shetland Islands

AbstractThis article presents the results of measurements of the components of ground-surface energy balance (radiation balance, sensible heat flux, latent heat flux, and ground heat flux) taken during the 1994/95 summer season at Poland's Henryk Arctowski Station, King George Island, South Shetland Islands (62°09'42”S, 58°28'10”W). This was the first time that these complex measurements had been taken in the central part of the South Shetlands archipelago. The results are evaluated at the level of daily and seasonal fluctuations. The consequences of energy balance on the temperature conditions of the soil substrata are highlighted. The verification of the degree of influence of a subset of energy-balance components on soil temperature allowed analysis of the relationships among soil temperature, radiation balance, and sensible heat flux. This analysis leads to the conclusion that there is a rapid reaction of the soil temperature to the radiation balance and sensible heat flux to a depth of 5 cm. The boundary atmosphere and soil substrate represent the basic components of the ecotops of the Antarctic vegetation oasis, so these results are interpreted in pedological or botanical studies in the search for environmental influences on the vegetation.

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Estimating Reflected and Emitted Components of the Radiation Balance Using Remotely-Sensed Spectral Data from Kurex-91

[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.1992.578336 ◽

2005 ◽

Cited By ~ 1

Author(s):

B.L. Blad ◽

E.A. Walter-Shea ◽

M.A. Mesareh ◽

C.J. Hays

Keyword(s):

Spectral Data ◽

Remotely Sensed ◽

Radiation Balance

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Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-2091-2013 ◽

2013 ◽

Vol 13 (4) ◽

pp. 2091-2113 ◽

Cited By ~ 108

Author(s):

J. E. Shilling ◽

R. A. Zaveri ◽

J. D. Fast ◽

L. Kleinman ◽

M. L. Alexander ◽

...

Keyword(s):

Mass Spectrometer ◽

Organic Aerosol ◽

Proton Transfer Reaction ◽

Chemical Mechanism ◽

Biogenic Emissions ◽

Anthropogenic Emissions ◽

Radiation Balance ◽

Particle Phase ◽

Aerosol Formation ◽

Research Aircraft

Abstract. The CARES campaign was conducted during June, 2010 in the vicinity of Sacramento, California to study aerosol formation and aging in a region where anthropogenic and biogenic emissions regularly mix. Here, we describe measurements from an Aerodyne High Resolution Aerosol Mass Spectrometer (AMS), an Ionicon Proton Transfer Reaction Mass Spectrometer (PTR-MS), and trace gas detectors (CO, NO, NOx) deployed on the G-1 research aircraft to investigate ambient gas- and particle-phase chemical composition. AMS measurements showed that the particle phase is dominated by organic aerosol (OA) (85% on average) with smaller concentrations of sulfate (5%), nitrate (6%) and ammonium (3%) observed. PTR-MS data showed that isoprene dominated the biogenic volatile organic compound concentrations (BVOCs), with monoterpene concentrations generally below the detection limit. Using two different metrics, median OA concentrations and the slope of plots of OA vs. CO concentrations (i.e., ΔOA/ΔCO), we contrast organic aerosol evolution on flight days with different prevailing meteorological conditions to elucidate the role of anthropogenic and biogenic emissions on OA formation. Airmasses influenced predominantly by biogenic emissions had median OA concentrations of 2.2 μg m−3 and near zero ΔOA/ΔCO. Those influenced predominantly by anthropogenic emissions had median OA concentrations of 4.7 μg m−3 and ΔOA/ΔCO ratios of 35–44 μg m−3 ppmv. But, when biogenic and anthropogenic emissions mixed, OA levels were enhanced, with median OA concentrations of 11.4 μg m−3 and ΔOA/ΔCO ratios of 77–157 μg m−3 ppmv. Taken together, our observations show that production of OA was enhanced when anthropogenic emissions from Sacramento mixed with isoprene-rich air from the foothills. After considering several anthropogenic/biogenic interaction mechanisms, we conclude that NOx concentrations play a strong role in enhancing SOA formation from isoprene, though the chemical mechanism for the enhancement remains unclear. If these observations are found to be robust in other seasons and in areas outside of Sacramento, regional and global aerosol modules will need to incorporate more complex representations of NOx-dependent SOA mechanisms and yields into their algorithms. Ultimately, accurately predicting OA mass concentrations and their effect on radiation balance will require a mechanistically-based treatment of the interactions of biogenic and anthropogenic emissions.

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Implications of aerosol-induced snow darkening on regional hydroclimate over the Himalayas

10.5194/egusphere-egu21-11972 ◽

2021 ◽

Author(s):

Vijayakumar Sivadasan Nair ◽

Usha Keshav Hasyagar ◽

Surendran Nair Suresh Babu

Keyword(s):

South Asia ◽

Climate Model ◽

Hydrological Cycle ◽

Monsoon Season ◽

Radiation Balance ◽

Western Himalayas ◽

Radiative Effect ◽

Anthropogenic Aerosols ◽

Snow Albedo ◽

Snow Cover Extent

The snow-covered mountains of Himalayas are known to play a crucial role in the hydrology of South Asia and are known as the &#8220;Asian water tower&#8221;. Despite the high elevations, the transport of anthropogenic aerosols from south Asia and desert dust from west Asia plays a significant role in directly and indirectly perturbing the radiation balance and hydrological cycle over the region. Absorbing aerosols like black carbon (BC) and dust deposited on the snow surface reduces the albedo of the Himalayan snow significantly (snow darkening or snow albedo effect). Using a Regional Climate Model (RegCM-4.6.0) coupled with SNow, ICe and Aerosol Radiation (SNICAR) module, the implications of aerosol-induced snow darkening on the regional hydroclimate of the Himalayas are investigated in this study. The aerosols deposited on snow shows a distinct regional heterogeneity. The albedo reduction due to aerosols shows a west to east gradient during pre-monsoon season and this results in the positive radiative effect of about 29 Wm-2, 17 Wm-2 and 5 Wm-2 over western, central and eastern Himalayas respectively. The reduction in the snow albedo also results in the sign reversal of the aerosol direct radiative effect i.e., from warming to cooling at the top of the atmosphere during pre-monsoon season. The excess solar energy trapped at the surface due to snow darkening warms the surface (0.66-1.9 K) and thus decreases the snow cover extent significantly. This results in the reduction of the number of snow-covered days by more than a month over the western Himalayas and about 10 &#8211; 15 days over the central Himalayas. The early snowmelt due to aerosol-induced snow darkening results in the increase of runoff throughout the melting season. Therefore, the present study highlights the heterogeneous response of aerosol induced snow albedo feedbacks over the Himalayan region and its impact on the snowpack and hydrology, which has further implications on the freshwater availability over the region.

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Can the Direct Effect of Aerosols Improve Subseasonal Predictability?

Monthly Weather Review ◽

10.1175/mwr-d-17-0282.1 ◽

2018 ◽

Vol 146 (10) ◽

pp. 3481-3498 ◽

Cited By ~ 8

Author(s):

Angela Benedetti ◽

Frédéric Vitart

Keyword(s):

Weather Prediction ◽

Ensemble Prediction ◽

Radiation Balance ◽

Carbonaceous Aerosols ◽

Madden Julian Oscillation ◽

Reasonable Accuracy ◽

Ensemble Prediction System ◽

Radiative Fluxes ◽

Aerosol Effect ◽

Definite Proof

Abstract The fact that aerosols are important players in Earth’s radiation balance is well accepted by the scientific community. Several studies have shown the importance of characterizing aerosols in order to constrain surface radiative fluxes and temperature in climate runs. In numerical weather prediction, however, there has not been definite proof that interactive aerosol schemes are needed to improve the forecast. Climatologies are instead used that allow for computational efficiency and reasonable accuracy. At the monthly to subseasonal range, it is still worth investigating whether aerosol variability could afford some predictability, considering that it is likely that persisting aerosol biases might manifest themselves more over time scales of weeks to months and create a nonnegligible forcing. This paper explores this hypothesis using the ECMWF’s Ensemble Prediction System for subseasonal prediction with interactive prognostic aerosols. Four experiments are conducted with the aim of comparing the monthly prediction by the default system, which uses aerosol climatologies, with the prediction using radiatively interactive aerosols. Only the direct aerosol effect is considered. Twelve years of reforecasts with 50 ensemble members are analyzed on the monthly scale. Results indicate that the interactive aerosols have the capability of improving the subseasonal prediction at the monthly scales for the spring/summer season. It is hypothesized that this is due to the aerosol variability connected to the different phases of the Madden–Julian oscillation, particularly that of dust and carbonaceous aerosols. The degree of improvement depends crucially on the aerosol initialization. More work is required to fully assess the potential of interactive aerosols to increase predictability at the subseasonal scales.

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