Effects of ice cover on the solar radiation regime in Canadian lakes

The article presents data on the study of the radiation regime and photosynthesis net productivity in the crown of an apple tree in connection with the regenerative pruning of old-aged trees. The object of the research was an apple tree of the Antonovka obyknovennaya variety, a seed stock (seedlings of cultivated varieties), planted in 1987. The test plot soil is leached chernozem. Options: 1. Established pruning (control); 2. Pruning for 5-6 year-old wood; 3. Pruning for 7-8 year-old wood. The experiment was arranged inrandomized blocks of 6 accounting trees in 3 replicates. The regenerative pruning was carried out in spring 2016. Every year damaged branches were removed in the control variant, while “wolf-like” shoots were thinned in other variants. The solar output was accounted within the daytime with the 2-hour interval from the northern and southern sides of the apple tree crown in its center, as well as under the crown at a distance of 1, 2 and 3 meters from the periphery to the center of the crown. The measurements were carried out after the growth activity cessation in the fine weather in August with a universal albedometer M-69 coming with a galvanometer GSA-1. The net productivity of leaves was determined by the method of A. S. Ovsyannikov in parallel, taking into account solar radiation. It is revealed that the regenerative pruning has a considerable impact on the performance of the solar output. The greatest arrival of solar radiation is noted on the periphery of the crown. In the treatment with pruning branches for 5-6 year-old wood, this parameter was 10.5-13.5 % higher than in the control variant. Pruning branches for 7-8 year-old wood improved lighting conditions by 27.6-31.7 % compared to the control. In the lower part of the crown, the radiation regime is less favorable for the photosynthesis process relative to the central part of the crown. Regenerative pruning increased the photosynthesis productivity significantly. In the central part of the crown, the highest parameters of the net photosynthesis productivity were observed on the periphery on the southern side when pruning for 7-8 year-old wood - 7.81 g of dry basis/m2 *day.

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A Regional Seasonal Forecast Model of Arctic Minimum Sea Ice Extent: Reflected Solar Radiation vs. Late Winter Coastal Divergence

Journal of Climate ◽

10.1175/jcli-d-20-0846.1 ◽

2021 ◽

pp. 1

Author(s):

Rachel Kim ◽

Bruno Tremblay ◽

Charles Brunette ◽

Robert Newton

Keyword(s):

Solar Radiation ◽

Sea Ice ◽

Open Water ◽

Forecast Model ◽

Ice Cover ◽

The Arctic ◽

Late Winter ◽

Coupled Models ◽

Sea Ice Extent ◽

Predictive Skill

AbstractThinning sea ice cover in the Arctic is associated with larger interannual variability in the minimum Sea Ice Extent (SIE). The current generation of forced or fully coupled models, however, have difficulty predicting SIE anomalies from the long-term trend, highlighting the need to better identify the mechanisms involved in the seasonal evolution of sea ice cover. One such mechanism is Coastal Divergence (CD), a proxy for ice thickness anomalies based on late winter ice motion, quantified using Lagrangian ice tracking. CD gains predictive skill through the positive feedback of surface albedo anomalies, mirrored in Reflected Solar Radiation (RSR), during melt season. Exploring the dynamic and thermodynamic contributions to minimum SIE predictability, RSR, initial SIE (iSIE) and CD are compared as predictors using a regional seasonal sea ice forecast model for July 1, June 1 and May 1 forecast dates for all Arctic peripheral seas. The predictive skill of June RSR anomalies mainly originates from open water fraction at the surface, i.e. June iSIE and June RSR have equal predictive skill for most seas. The finding is supported by the surprising positive correlation found between June Melt Pond Fraction (MPF) and June RSR in all peripheral seas: MPF anomalies indicate presence of ice or open water that is key to creating minimum SIE anomalies. This contradicts models that show correlation between melt onset, MPF and the minimum SIE. A hindcast model shows that for a May 1 forecast, CD anomalies have better predictive skill than RSR anomalies for most peripheral seas.

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Potential and Use of Solar Energy in Primorye Region (Russia)

Solar Energy ◽

10.1115/isec2004-65058 ◽

2004 ◽

Author(s):

Oleg P. Kovalev ◽

Alexandr V. Volkov

Keyword(s):

Solar Radiation ◽

Solar Energy ◽

Hot Water ◽

Solar Collectors ◽

Heating Systems ◽

Primorye Region ◽

Solar Radiation Flux ◽

Radiation Regime ◽

The Given

During long-term time, the laboratory of non-traditional energetic is been busy with development and introduction of solar water heating systems for hot water supply. The systems with solar collectors of 40 m2 area have been developed and introducted. For estimation of their efficiency we should know flux density of solar radiation, proceeding to surface at the given place. However in Primorye Region at actinometrical watching only four meteostations in the Southern part are carrying out straight measurements of solar radiation flux, and the others record data which concern only solar radiation regime (the amount of solar radiation hours, relation of watching duration of solar radiation to possible duration, the amount of days without sun, etc.). We suggested the expression, which according to know data of solar radiation and cloudiness, recorded practically on all meteorological stations gives possibility to calculate for Primorye Region month sums of total radiation proceeding to horizontal surface. The comparison of estimated values with measured ones gives the error to 3...9% with regard to average many years values, and are in the range of variability of measured values for separate years. In Primorye Region more than 250 m2 of solar collectors were installed; and among them 150 m2 were developed with the laboratory, to position on 2003.11.01. NOTE: This paper was presented at the 2004 International Solar Energy Conference and was inadvertently omitted from the 2004 ASME proceedings. The page range refers to the 2005 International Solar Energy Conference Print Proceedings, where it was subsequently published.

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Arctic sea-ice conditions and the distribution of solar radiation during summer

Annals of Glaciology ◽

10.1017/s0260305500014439 ◽

1997 ◽

Vol 25 ◽

pp. 445-450 ◽

Cited By ~ 11

Author(s):

Donald K. Perovich ◽

Walter B. Tucker

Keyword(s):

Solar Radiation ◽

Sea Ice ◽

Open Water ◽

Ice Cover ◽

Feedback Mechanism ◽

Arctic Sea Ice ◽

The Arctic ◽

Melt Ponds ◽

Arctic Ice ◽

Median Area

Understanding the interaction of solar radiation with the ice cover is critical in determining the heat and mass balance of the Arctic ice pack, and in assessing potential impacts due to climate change. Because of the importance of the ice-albedo feedback mechanism, information on the surface state of the ice cover is needed. Observations of the surface slate of sea ice were obtained from helicopter photography missions made during the 1994 Arctic Ocean Section cruise. Photographs from one flight, taken during the height of the melt season (31 July 1994) at 76° N, 172° W, were analyzed in detail. Bare ice covered 82% of the total area, melt ponds 12%, and open water 6%, There was considerable variability in these area fractions on scales < 1 km2. Sample areas >2 3 km2gave representative values of ice concentration and pond fraction. Melt ponds were numerous, with a number density of 1800 ponds km-2. The melt ponds had a mean area of 62 m2a median area of 14 m2, and a size distribution that was well lit by a cumulative lognormal distribution. While leads make up only a small portion of the total area, they are the source of virtually all of the solar energy input to the ocean.

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Dynamics of gaseous elemental mercury during polar spring and winter

10.5194/egusphere-egu2020-1386 ◽

2020 ◽

Author(s):

Fidel Pankratov ◽

Alexander Mahura ◽

Valentin Popov ◽

Vladimir Masloboev

Keyword(s):

Surface Layer ◽

Solar Activity ◽

Solar Radiation ◽

Solar Energy ◽

Mercury Concentration ◽

Elemental Mercury ◽

Ice Cover ◽

Photochemical Reactions ◽

High Solar Activity ◽

Gaseous Elemental Mercury

Dynamics of gaseous elemental mercury during polar spring and winterSince June 2001 the long-term monitoring of the gaseous elemental mercury (thereafter, mercury) in the surface layer of the atmospheric has been conducted near the Amderma settlement (69,72&#208;&#190;N; 61,62oE; Yugor Peninsula, Russia).During this monitoring, variations of the lowered mercury concentrations (<1.0 ng m-3) were observed for spring (March&#8211;May) period in 2005 and 2011. For spring 2005, the intensity of the solar radiation did not affect the number of low values of mercury concentrations. With an increase of solar activity during the day there was a reverse effect: i.e. from 9 until 15 h the number of lowered values of concentration decreased. For the evening hours, the highest number of lowered concentrations and atmospheric mercury depletion events, AMDEs (12 events) were observed. For 2005, upon reaching a daily high solar activity the processes of mercury depletion were not observed. It could be because lacking of a large number of marine aerosols in the atmospheric surface layer, although the processes of photochemical reactions did not stop. For spring 2011, during increased solar activity the number of AMDEs increased to 62 events. However, there was no ice cover observed in the coastal area, and consequently, large amounts of sea aerosol could be presented in the surface layer of the atmosphere.For the winter (December-January) period, the maximum number (in total, 495) of lowered values of mercury concentration and AMDEs (32 events) were recorded in 2010&#8211;2011. Such situation was previously observed only in winter of 2006&#8211;2007 (13 events). As there is no direct sunlight in mentioned period, the removal of mercury from the atmosphere may be caused by combination of physical and chemical processes that are not related to photochemistry. Starting mid-January, although duration of the day increases, but solar energy is not enough to activate photochemical reactions and predominant type of solar radiation is diffuse rather than direct one. However, AMDEs were still reported at that time (18 events were registered in January 2011).After mid-March, the angle of sun&#8217;s declination increases and the incoming solar energy is sufficient to activate photochemistry. However, during March&#8211;May there was no linear relationship identified for AMDEs. The maximum number (300) of lowered values of mercury concentration and AMDEs (21 events, with duration up to 66 hours) were registered in April. Such AMDEs are connected with presence of elevated concentrations of aerosols in the absence of ice cover in the marine coastal zone. Not excluded a possibility of contribution of anthropogenic aerosols (from burning of fossil fuels) in the process of mercury deposition from the atmosphere on the underlying surface.

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Optical properties of the ice cover on Vendyurskoe lake, Russian Karelia (1995–2012)

Annals of Glaciology ◽

10.3189/2013aog62a179 ◽

2013 ◽

Vol 54 (62) ◽

pp. 121-124 ◽

Cited By ~ 6

Author(s):

G. Zdorovennova ◽

R. Zdorovennov ◽

N. Palshin ◽

A. Terzhevik

Keyword(s):

Optical Properties ◽

Solar Radiation ◽

Ice Sheet ◽

Ice Cover ◽

Late Winter ◽

Lake Ecosystem ◽

Attenuation Coefficients ◽

Quasi Newton ◽

Northwestern Russia

AbstractSolar radiation penetrating the ice is one of the most important factors that determine the functioning of lake ecosystem in late winter. Parameterization of the attenuation of solar radiation in the snow-ice sheet is an essential tool in the study of the light regime of ice-covered lakes. The optical properties of the snow-ice sheet in Vendyurskoe lake, northwestern Russia, are investigated on the basis of long-term field observations (1995–2012). The four-layer approach (snow, white ice, slush and congelation ice) is used to study the attenuation of the downwelling planar irradiance in the snow-ice sheet. The bulk attenuation coefficients for four layers (18.8 m–1 for snow, 6 m−1 for white ice, 3.5 m−1 for slush and 2.1 m−1 for congelation ice) are calculated by the quasi-Newton method. A comparison of observed and calculated values of the irradiance beneath the ice shows that the determined coefficients adequately describe the attenuation of the downwelling irradiance by snow-ice cover.

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Tibetan Plateau Lakes as Heat Flux Hot Spots

Eos ◽

10.1029/2021eo162931 ◽

2021 ◽

Vol 102 ◽

Author(s):

Kate Wheeling

Keyword(s):

Heat Flux ◽

Tibetan Plateau ◽

Solar Radiation ◽

Hot Spots ◽

Ice Cover ◽

Freshwater Lakes ◽

The World ◽

Intense Solar Radiation

Freshwater lakes on the highest plateau in the world act like lenses that accumulate heat from the intense solar radiation, accelerating ice cover melt and affecting land-atmosphere fluxes.

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