Quantifying low rates of summertime sublimation for buried glacier ice in Beacon Valley, Antarctica

2006 ◽  
Vol 18 (3) ◽  
pp. 421-428 ◽  
Author(s):  
D.E. Kowalewski ◽  
D.R Marchant ◽  
J.S. Levy ◽  
J.W. Head
Keyword(s):  
Relative Humidity ◽  
Soil Temperature ◽  
Meteorological Data ◽  
Thick Layer ◽  
Atmospheric Temperature ◽  
Dry Valleys ◽  
Term Survival ◽  
Study Interval ◽  
Glacier Ice ◽  
Taylor Glacier

A remnant of Taylor Glacier ice rests beneath a 40–80 cm thick layer of sublimation till in central Beacon Valley, Antarctica. A vapour diffusion model was developed to track summertime vapour flow within this till. As input, we used meteorological data from installed HOBO data loggers that captured changes in solar radiance, atmospheric temperature, relative humidity, soil temperature, and soil moisture from 18 November 2004–29 December 2004. Model results show that vapour flows into and out of the sublimation till at rates dependent on the non-linear variation of soil temperature with depth. Although measured meteorological conditions during the study interval favoured a net loss of buried glacier ice (∼0.017 mm), we show that ice preservation is extremely sensitive to minor perturbations in temperature and relative humidity. Net loss of buried glacier ice is reduced to zero (during summer months) if air temperature (measured 2 cm above the till surface) decreases by 5.5°C (from −7°C to −12°C); or average relative humidity increases by 22% (from ∼36% to 58%); or infiltration of minor snowmelt equals ∼0.002 mm day−1. Our model results are consistent with the potential for long-term survival of buried glacier ice in the hyper-arid stable upland zone of the western Dry Valleys.

scholarly journals Buried ice in Kennar Valley: a late Pleistocene remnant of Taylor Glacier

2017 ◽  
Vol 29 (3) ◽  
pp. 239-251 ◽  
Author(s):  
Kate M. Swanger
Keyword(s):  
Late Pleistocene ◽  
Ice Cores ◽  
Dry Valleys ◽  
Patterned Ground ◽  
Outlet Glacier ◽  
Air Bubble ◽  
Isotopic Analyses ◽  
Stable Isotopic ◽  
Glacier Ice ◽  
Taylor Glacier

AbstractBuried glacier ice is common in the McMurdo Dry Valleys and under ideal climatic and geomorphological conditions may be preserved for multimillion-year timescales. This study focuses on the analysis of ~300 m2 of buried glacier ice in lower Kennar Valley, Quartermain Range. The mapped ice is clean,<10 m thick and covered by a~25 cm sandy drift. The mouth of Kennar Valley is occupied by a lobe of Taylor Glacier, an outlet glacier from Taylor Dome. Based on ice–sediment characteristics, air bubble concentrations and stable isotopic analyses from three ice cores, the lower Kennar Valley ice is glacial in origin. These data coupled with a previously reported exposure age chronology indicate that the buried ice was deposited by a late Pleistocene advance of Taylor Glacier, probably during an interglacial interval. The surface of the buried glacier ice exhibits a patterned ground morphology characterized by small, dome-shaped polygons with deep troughs. This shape possibly reflects the final stages of ice loss, as stagnant, isolated ice pinnacles sublimate in place. This study highlights how polygon morphology can be used to infer the thickness of clean buried ice and its geomorphological stability throughout Antarctica, as well as other in cold, arid landscapes.

scholarly journals Soil CO2 Emission under Different Tillage Practices in Major Soils of Kerala

2020 ◽  
pp. 1-12
Author(s):  
S. Toufeeq ◽  
D. Dhalin ◽  
Seena R. Subhagan ◽  
Dipak S. Khatawkar ◽  
B. Aparna ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Soil Temperature ◽  
Bulk Density ◽  
Paddy Field ◽  
Co2 Emission ◽  
Atmospheric Temperature ◽  
Field Soil ◽  
Tillage Practices ◽  
Paddy Field Soil

International responsibility is increasing in India to adopt a more pro-active role in greenhouse gas emission. Hence, it is important to develop a clear understanding of our emission inventory towards reducing Carbon dioxide (CO2) emissions. Soils are an important pool of active carbon and tillage can lead to carbon emission from agricultural soils. This study assess the quantity of CO2 release from three major soils (red loam, coastal sandy and paddy field soil) of Kerala under different tillage practices(conventional, with cultivator and with rotovator) and to optimize the tillage practices with minimum CO2 emission. The CO2emission from soil surfaces was measured using base trap method with Sodium hydroxide (NaOH) as base. The influence of soil temperature, soil moisture content, organic matter in soil, soil pH, bulk density, atmospheric temperature and relative humidity on CO2 emission was assessed. The conventional tillage resulted in the maximum CO2 emission followed by the tillage with cultivator and the least value was observed when tilled with rotovator. The maximum CO2 emission was observed in the paddy field soil followed by red loam and the least value was observed from the coastal sandy. The major quantity of CO2 was released just after the breakage of soil in all kind of tillage methods and became almost equal to the undisturbed condition after two hours of ploughing. The bulk density of soil was negatively correlated, organic carbon content was positively correlated, soil temperature was positively correlated and atmospheric temperature was positively correlated with CO2 emission from the red loam soil in all the tillage practices. No significant correlation was obtained between relative humidity and soil moisture with CO2emission.Tillage with rotovator contributed the minimum CO2 to atmosphere and significantly affects the concentration of CO2in the atmosphere, ultimately contribute in mitigation of global warming.

scholarly journals Meteorological Models for Determination of Surface Radio Refractivity over Nigeria

2019 ◽  
pp. 1-15 ◽  
Author(s):  
O. O. Ajileye ◽  
O. S. Popoola ◽  
F. F. Kayode ◽  
A. B. Rabiu
Keyword(s):  
Relative Humidity ◽  
Meteorological Data ◽  
Atmospheric Temperature ◽  
Climatic Conditions ◽  
The South ◽  
Meteorological Model ◽  
The North ◽  
Modern Era ◽  
Meteorological Models

Previous studies showed that linear meteorological expressions obtained were localized and could not be generally applied. It is therefore required that more locations should be investigated to deduce new linear meteorological models best suitable for estimation of surface refractivity. Surface meteorological data, including pressure, temperature and relative humidity, was downloaded from Modern-Era Retrospective analysis for Research and Application (MERRA - 2) for six locations defined by different climatic conditions over Nigeria, namely Yenagoa, Abakaliki, Ibadan, Anyigba, Jalingo and Sokoto for a period of 40 years partitioned into two periods of 20 years each. The 1979 – 1998 dataset of atmospheric temperature, T (K), atmospheric pressure, P (hPa) and relative humidity, Rh (%) were extracted using text import wizard to calculate surface refractivity using existing model (Nitu-r). Regression analysis was carried out to obtain new linear meteorological expressions as function of temperature (Nt), relative humidity (Nrh), and combination of relative humidity and temperature (Nrh,t). The new expressions were tested using 1999 – 2018 meteorological dataset and the results of surface refractivity from the new linear expressions were compared with values from existing equations. It was observed that high relative humidity and low temperature values prevalent in the three southern stations – Yenagoa, Abakaliki and Ibadan – significantly enhanced the suitability of Nrh,t linear meteorological model for estimation of surface refractivity values comparable toNitu-r. Contrary to the observations in the southern stations, in the northern stations, relative humidity contributions (Nrh) had the best linear correlation of 0.96 at Anyigba, 0.98 at Jalingo and Sokoto. Estimation of surface refractivity from the new linear meteorological models was found to be best as a function of temperature and relative humidity in the south and a function of relative humidity in the north. Linear meteorological models as a function of relative humidity and temperature were best suitable for stations in the south with minimum correlation of 0.98 while linear expressions as a function of relative humidity only were best suitable for the stations in the north with minimum correlation of 0.96.

scholarly journals Basic Diagnosis and Prediction of Persistent Contrail Occurrence Using High-Resolution Numerical Weather Analyses/Forecasts and Logistic Regression. Part II: Evaluation of Sample Models

2009 ◽  
Vol 48 (9) ◽  
pp. 1790-1802 ◽  
Author(s):  
David P. Duda ◽  
Patrick Minnis
Keyword(s):  
Relative Humidity ◽  
Wind Direction ◽  
Meteorological Data ◽  
Logistic Models ◽  
Satellite Observations ◽  
Lapse Rate ◽  
Prediction System ◽  
Advanced Regional Prediction System ◽  
Regional Prediction ◽  
Surface Models

Abstract A probabilistic forecast to accurately predict contrail formation over the conterminous United States (CONUS) is created by using meteorological data based on hourly meteorological analyses from the Advanced Regional Prediction System (ARPS) and the Rapid Update Cycle (RUC) combined with surface and satellite observations of contrails. Two groups of logistic models were created. The first group of models (SURFACE models) is based on surface-based contrail observations supplemented with satellite observations of contrail occurrence. The most common predictors selected for the SURFACE models tend to be related to temperature, relative humidity, and wind direction when the models are generated using RUC or ARPS analyses. The second group of models (OUTBREAK models) is derived from a selected subgroup of satellite-based observations of widespread persistent contrails. The most common predictors for the OUTBREAK models tend to be wind direction, atmospheric lapse rate, temperature, relative humidity, and the product of temperature and humidity.

scholarly journals Evidence for subglacial ponding across Taylor Glacier, Dry Valleys, Antarctica

2004 ◽  
Vol 39 ◽  
pp. 79-84 ◽  
Author(s):  
Alun Hubbard ◽  
Wendy Lawson ◽  
Brian Anderson ◽  
Bryn Hubbard ◽  
Heinz Blatter
Keyword(s):  
Equipotential Surface ◽  
Dry Valleys ◽  
Flow Paths ◽  
Dielectric Contrast ◽  
Pressure Melting ◽  
Reflective Power ◽  
Taylor Glacier ◽  
High Dielectric ◽  
Ice Water ◽  
Modelling Data

AbstractIce-penetrating radar and modelling data are presented suggesting the presence of a zone of temperate ice, water ponding or saturated sediment beneath the tongue of Taylor Glacier, Dry Valleys, Antarctica. The proposed subglacial zone lies 3–6 km up-glacier of the terminus and is 400– 1000m across. The zone coincides with an extensive topographic overdeepening to 80m below sea level. High values of residual bed reflective power across this zone compared to other regions and the margins of the glacier require a high dielectric contrast between the ice and the bed and are strongly indicative of the presence of basal water or saturated sediment. Analysis of the hydraulic equipotential surface also indicates strong convergence into this zone of subglacial water flow paths. However, thermodynamic modelling reveals that basal temperatures in this region could not exceed –7˚C relative to the pressure-melting point. Such a result is at odds with the radar observations unless the subglacial water is a hypersaline brine.

Statistical Analysis of Weather Effects on PM2.5

2012 ◽  
Vol 610-613 ◽  
pp. 1033-1040
Author(s):  
Wei Dai ◽  
Jia Qi Gao ◽  
Bo Wang ◽  
Feng Ouyang
Keyword(s):  
Statistical Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Statistical Methods ◽  
Predictive Analytics ◽  
Hypothesis Test ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Statistical Distribution ◽  
Weather Effects

Effects of weather conditions including temperature, relative humidity, wind speed, wind and direction on PM2.5 were studied using statistical methods. PM2.5 samples were collected during the summer and the winter in a suburb of Shenzhen. Then, correlations, hypothesis test and statistical distribution of PM2.5 and meteorological data were analyzed with IBM SPSS predictive analytics software. Seasonal and daily variations of PM2.5 have been found and these mainly resulted from the weather effects.

scholarly journals Brief communication: Rare ambient saturation during drifting snow occurrences at a coastal location of East Antarctica

2019 ◽  
Vol 13 (12) ◽  
pp. 3405-3412 ◽  
Author(s):  
Charles Amory ◽  
Christoph Kittel
Keyword(s):  
Relative Humidity ◽  
Meteorological Data ◽  
Ice Sheet ◽  
Ambient Air ◽  
East Antarctica ◽  
Strong Increase ◽  
Katabatic Wind ◽  
Strong Wind ◽  
Near Surface ◽  
Drifting Snow

Abstract. Sublimation of snow particles during transport has been recognized as an important ablation process on the Antarctic ice sheet. The resulting increase in moisture content and cooling of the ambient air are thermodynamic negative feedbacks that both contribute to increase the relative humidity of the air, inhibiting further sublimation when saturation is reached. This self-limiting effect and the associated development of saturated near-surface air layers in drifting snow conditions have mainly been described through modelling studies and a few field observations. A set of meteorological data, including drifting snow mass fluxes and vertical profiles of relative humidity, collected at site D17 in coastal Adélie Land (East Antarctica) during 2013 is used to study the relationship between saturation of the near-surface atmosphere and the occurrence of drifting snow in a katabatic wind region that is among the most prone to snow transport by wind. Atmospheric moistening by the sublimation of the windborne snow particles generally results in a strong increase in relative humidity with the magnitude of drifting snow and a decrease in its vertical gradient, suggesting that windborne-snow sublimation can be an important contributor to the local near-surface moisture budget. Despite a high incidence of drifting snow at the measurement location (60.1 % of the time), saturation, when attained, is however most often limited to a thin air layer below 1 m above ground. The development of a near-surface saturated air layer up to the highest measurement level of 5.5 m is observed in only 8.2 % of the drifting snow occurrences or 6.3 % of the time and mainly occurs in strong wind speed and drift conditions. This relatively rare occurrence of ambient saturation is explained by the likely existence of moisture-removal mechanisms inherent to the katabatic and turbulent nature of the boundary-layer flow that weaken the negative feedback of windborne-snow sublimation. Such mechanisms, potentially quite active in katabatic-generated windborne-snow layers all over Antarctica, may be very important in understanding the surface mass and atmospheric moisture budgets of the ice sheet by enhancing windborne-snow sublimation.

scholarly journals Influence of meteorological parameters on wheat yield under different sowing conditions

MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 161-172
Author(s):  
ANANTA VASHISTH ◽  
DEBASISH ROY ◽  
AVINASH GOYAL ◽  
P. KRISHNAN
Keyword(s):  
Relative Humidity ◽  
Soil Temperature ◽  
Air Temperature ◽  
Field Experiments ◽  
Wheat Yield ◽  
Weather Condition ◽  
Grain Filling ◽  
Crop Growth ◽  
Leaf Water ◽  
Growth Stages

Field experiments were conducted on the research farm of IARI, New Delhi during Rabi 2016-17 and 2017-18. Three varieties of wheat (PBW-723, HD-2967 and HD-3086) were sown on three different dates for generating different weather condition during various phenological stages of crop. Results showed that during early crop growth stages soil moisture had higher value and soil temperature had lower value and with progress of crop growth stage, the moisture in the upper layer decreased and soil temperature increased significantly as compared to the bottom layers. During tillering and jointing stage, air temperature within canopy was more and relative humidity was less while during flowering and grain filling stage, air temperature within canopy was less and relative humidity was more in timely sown crop as compared to late and very late sown crop. Radiation use efficiency and relative leaf water content had significantly higher value while leaf water potential had lower value in timely sown crop followed by late and very late sown crop. Yield had higher value in HD-3086 followed by HD-2967 and PBW-723 in all weather conditions. Canopy air temperature difference had positive value in very late sown crop particularly during flowering and grain-filling stages. This reflects in the yield. Yield was more in timely sown crop as compared to late and very late sown crop.  

scholarly journals Cultivation of Milky Mushroom (Calocybeindica) in Greenhouse

2021 ◽  
pp. 63-69
Author(s):  
P. Indraja ◽  
M. Madhava ◽  
S. Satyam ◽  
P. R. Chandra ◽  
S. Joy Prince
Keyword(s):  
Relative Humidity ◽  
Traditional Method ◽  
Large Scale ◽  
Nutritive Value ◽  
Edible Mushroom ◽  
Atmospheric Temperature ◽  
The Other ◽  
Controlled Environment ◽  
Mushroom Cultivation ◽  
Experimental Conditions

Mushroom cultivation is one of the most important steps in diversification of agriculture. Milky mushroom (Calocybeindica) is a tropical edible mushroom, popular because of its good nutritive value and it can be cultivated commercially on large scale. Generally, by creating controlled environment in rooms mushroom cultivation is taken up, In traditional method  it is typical to manage the atmospheric temperature and humidity in desired range, which can be maintained easily in greenhouse by automatic control system.Cultivation of milky mushroom in greenhouse was taken up in controlled environment under three different conditions of controlled temperature and relative humidity (RH). The experimental conditions are 28°C and 79% RH, 24°C and 84% RH and 32°C and 72%RH. The yield obtained was found maximum at 24°C temperature and 84% relative humidity when compared with the other two greenhouse environment conditions. The yield from the mushroom cultivation under controlled environmental conditions in greenhouse was found to be high when compared with the conventional practice. It was concluded that, the mushroom cultivation yields high under controlled greenhouse conditions and also economical compared to the conventional method.

scholarly journals CONSTRUCCIÓN DE UNA VIVIENDA SOLAR EN BASE A LAS PROPIEDADES TERMOFISICAS Y EVALUACIÓN EXPERIMENTAL DE SU CONFORT TÉRMICO EN ILAVE

2014 ◽  
Vol 16 (01) ◽  
Author(s):  
ARTURO FLORES CONDORI
Keyword(s):  
Relative Humidity ◽  
Solar Energy ◽  
Thermal Comfort ◽  
Thermophysical Properties ◽  
Experimental Evaluation ◽  
Meteorological Data ◽  
Thermal Inertia ◽  
Living Condition ◽  
Simulation Software ◽  
Experimental Structure

<h4 class="text-primary">Resumen</h4><p style="text-align: justify;">El presente artículo consistió en la construcción de una vivienda solar pasivo a base de propiedades termofísicas (Conductividad térmica, calor específico, difusividad térmica y inercia térmica) y desarrollar una evaluación experimental del rendimiento térmico aportado por los elementos constructivos, en una comunidad rural Colloco - Ilave, provisto de adecuado aislamiento térmico en la envolvente (doble pared de adobe, en el cielo raso: paja­carrizo-yeso y en el piso: tierra apisonada-cama de piedra-plástico-paja y totora), ubicación, la orientación y un sistema de acumulación de energía adecuadamente diseñada a base a encapsulado de piedras andesitas porosas y de totora. La distribución de energía calorífica almacenada fue primordial al ambiente dormitorio que esto permite el aprovechamiento de la energía solar para lograr que la temperatura al interior de la vivienda sea más confortable. Se realizó el análisis del comportamiento térmico de la vivienda construida y la vivienda rural típica, para lo cual se tomaron los datos meteorológicos de la zona (temperatura, humedad relativa, velocidad del viento y radiación solar), también se registraron la temperatura y humedad relativa del aire en el ambiente interior y exterior de las viviendas desde 19 de junio al 02 de julio del 2013. Obteniéndose en la vivienda construida las temperaturas máximas y mínimas de 15.85ºC y 11.88ºC respectivamente. Según la evaluación de la vivienda construida se aprecia un incremento de temperatura mínimo de 6.26°C, respecto a la vivienda típica. Para validar estos resultados experimentales, se ha utilizado el programa de simulación térmica EnergyPlus para los datos meteorológicos de la zona (3 868 msnm), comprobándose por el método correlativo, el factor de correlación fue r=0.92575. Este incremento de la temperatura en el interior de la vivienda construida contribuye alcanzar un confort térmico, permitiendo una condición de vida saludable para el poblador rural.</p><p><strong>PALABRAS CLAVE: </strong>* confort térmico * energía solar * propiedades termofísica * simulación térmica</p><h4 class="text-primary">ABSTRACT</h4><p><strong>CONSTRUCTION OF A SOLAR DWELLING BASED ON THERMOPHYSICAL PROPERTIES AND EXPERIMENTAL EVALUATION OF THERMAL COMFORT - ILAVE, PUNO - PERU»</strong></p><p style="text-align: justify;">The present article consists in the construction of a passive solar house based on the study of thermophysical properties (thermal conductivity, specific heat, thermal diffusivity and thermal inertia). We developed an experimental evaluation of the thermal efficiency contributed by different constructive materials, In the rural community of Colloco - Ilave. Once adequate thermal insulation was provided in the enveloping surface (double wall construction of sun-dried adobe brick, a false ceiling with: straw, bamboo and plaster. In the floor: tamped soil, stone bed, plastic, straw and totora reed). Location and position of the solar home in coordination with an energy accumulation system adequately designed with an encapsulation of porous Andesitic stones and Totora reed. Distribution of the stored thermal energy was directed primarily to the main bedroom, this enabled adequate use of solar energy in order to achieve a comfortable temperature within the dwelling. We analyzed the thermal behavior of both this experimental structure and that of a common rural dwelling; taking the interior and exterior meteorological readings found in the two dwelling types. (temperature, relative humidity, wind velocity and solar radiation). Between June 19th and July 2nd, the temperature and relative humidity of the interior of the experimental structure measured a max. of 15.85ºC (60.53ºF) and 11.88ºC (53.384ºF) respectively. According to a general evaluation of the experimental structure, there was a temperature increment of 6.26°C (=¿?ºF) compared to the average temperature of a normal dwelling. In order to confirm these experimental results we used the thermic simulation software EnergyPlus, entering the meteorological data of the area (3,868 meters above sea level=12690.3 ft.) using the correlative method and a correlative factor of r=0.92575. This higher temperature inside of the experimental structure contributes to attaining a thermic comfort allowing for a healthy living condition for the rural inhabitant.</p><p><strong>KEY WORDS: </strong>* thermal comfort * solar energy * thermophysical properties * thermal simulation</p>

Sign in / Sign up

Export Citation Format

Share Document