Focus on Thermokarst Lakes in Indian Himalaya: Inception and Implication under Warming Climate

2020 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Pratima Pandey ◽  
S. Nawaz Ali ◽  
Vikram Sharma ◽  
Prashant K. Champati Ray
Keyword(s):  
Western Himalaya ◽  
High Mountain ◽  
Thermokarst Lakes ◽  
Glacial Environments ◽  
Global Warming Scenario ◽  
Scientific Attention ◽  
Topographic Depressions ◽  
Permafrost Thawing ◽  
The Impact ◽  
Thaw Lakes

Thermokarst (Thaw) lakes are landforms found in topographic depressions created by thawing ground ice in permafrost zones. They play an important role in the regulation of climatic functions. These lakes are a manifestation of warming surface temperatures that accelerates the ice-rich permafrost to degrade by creating marshy hollows/ponds. In the current global warming scenario, the thermokarst lakes in the high mountain regions (Himalaya) are expected to grow further. This accelerate permafrost thawing which will affect the carbon cycle, hydrology and local ecosystems. This phenomenon has attracted huge scientific attention because it has led to a rapid mass change of glaciers in the region, including extensive changes occurring on peri-glacial environments. The most striking fact is the release of an enormous amount of greenhouse gases, including methane, carbon dioxide and nitrous oxide that is locked in these lakes. The present study delves into the thermokarst lakes in the upper reaches of Chandra Valley and Western Himalaya. The study also aims at designating the impact of their changes on the ecosystem, particularly their influence on the atmospheric greenhouse gas concentrations.

Influence of climate change on soil erosion in high mountain area: a case study of upper Heihe river basin

2021 ◽  
Author(s):  
Li Wang ◽  
Fan Zhang ◽  
Guanxing Wang
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
River Basin ◽  
Effect Of Temperature ◽  
Heihe River ◽  
High Mountain ◽  
Mountain Area ◽  
Impact Of Climate Change ◽  
High Mountain Area ◽  
The Impact

<p>The impact of climate change on soil erosion is pronounced in high mountain area. In this study, the revised universal soil loss equation (RUSLE) model was improved for better calculation of soil erosion during snowmelt period by integrating a distributed hydrological model in upper Heihe river basin (UHRB). The results showed that the annual average soil erosion rate from 1982 to 2015 in the study area was 8.1 t ha<sup>-1 </sup>yr<sup>-1</sup>, belonging to the light grade. To evaluate the influence of climate change on soil erosion, detrended analysis of precipitation, temperature and NDVI was conducted. It was found that in detrended analysis of precipitation and temperature, the soil erosion of UHRB would decrease 26.5% and 3.0%, respectively. While in detrended analysis of NDVI, soil erosion would increase 9.9%. Compared with precipitation, the effect of temperature on total soil erosion was not significant, but the detrended analysis of temperature showed that the effect of temperature on soil erosion during snowmelt period can reach 70%. These finding were helpful for better understanding of the impact of climate change on soil erosion and provide a scientific basis for soil management in high mountain area under climate change in the future.</p>

Empirical Literature on Economic Growth, 1991–2020: Uncovering Extant Gaps and Avenues for Future Research

2021 ◽  
pp. 097491012110616
Author(s):  
Natalia I. Doré ◽  
Aurora A. C. Teixeira
Keyword(s):  
Economic Growth ◽  
Latin American ◽  
Empirical Studies ◽  
Empirical Literature ◽  
Future Research ◽  
Long Run ◽  
Scientific Attention ◽  
The Impact ◽  
Determinants Of Economic Growth ◽  
Latin American And Caribbean

The factors required to achieve sustainable economic growth in a country are debated for decades, and empirical research in this regard continues to grow. Given the relevance of the topic and the absence of a comprehensive, systematic literature review, we used bibliometric techniques to examine and document several aspects in the empirical literature related to growth, from 1991 to 2020. Five main results are worth highlighting: (a) the share of empirical articles on economic growth show a clear upward trend; (b) among all the groups of countries considered, the emerging economies (EEs) have received the most scientific attention; (c) the economic growth processes of the Latin American and Caribbean EEs have observed negligible scientific attention; (d) the very long-run studies comprise a residual share among the empirical literature on growth; (e) the extant empirical studies on economic growth have addressed mainly the impact of “macroeconomic conditions.” Our findings suggest there is a need to redirect the empirical growth agenda, so as to encourage more scientific attention devoted to the analysis of key determinants of economic growth in the very long run. There should also be increased scrutiny of the processes of economic growth in Latin American and Caribbean EEs

scholarly journals NO<sub>2</sub> seasonal evolution in the North Subtropical free troposphere

2015 ◽  
Vol 15 (10) ◽  
pp. 14473-14504
Author(s):  
M. Gil-Ojeda ◽  
M. Navarro-Comas ◽  
L. Gómez-Martín ◽  
J. A. Adame ◽  
A. Saiz-Lopez ◽  
...  
Keyword(s):  
Optical Absorption Spectroscopy ◽  
High Mountain ◽  
Horizontal Line ◽  
Free Troposphere ◽  
Seasonal Evolution ◽  
The North ◽  
Measuring Period ◽  
The Impact ◽  
Pollution Events

Abstract. Three years of Multi-Axis Differential Optical Absorption Spectroscopy (MAXDOAS) measurements (2011–2013) have been used for estimating the NO2 mixing ratio along a horizontal line of sight from the high mountain Subtropical observatory of Izaña, at 2370 m a.s.l. (NDACC station, 28.3° N, 16.5° W). The method is based on horizontal path calculation from the O2–O2 collisional complex at the 477 nm absorption band which is measured simultaneously to the NO2, and is applicable under low aerosols loading conditions. The MAXDOAS technique, applied in horizontal mode in the free troposphere, minimizes the impact of the NO2 contamination resulting from the arrival of MBL airmasses from thermally forced upwelling breeze during central hours of the day. Comparisons with in-situ observations show that during most of measuring period the MAXDOAS is insensitive or very little sensitive to the upwelling breeze. Exceptions are found during pollution events under southern wind conditions. On these occasions, evidence of fast efficient and irreversible transport from the surface to the free troposphere is found. Background NO2 vmr, representative of the remote free troposphere, are in the range of 20–45 pptv. The observed seasonal evolution shows an annual wave where the peak is in phase with the solar radiation. Model simulations with the chemistry-climate CAM-Chem model are in good agreement with the NO2 measurements, and are used to further investigate the possible drivers of the NO2 seasonality observed at Izaña.

The Landfall and Inland Penetration of a Flood-Producing Atmospheric River in Arizona. Part I: Observed Synoptic-Scale, Orographic, and Hydrometeorological Characteristics

2013 ◽  
Vol 14 (2) ◽  
pp. 460-484 ◽  
Author(s):  
Paul J. Neiman ◽  
F. Martin Ralph ◽  
Benjamin J. Moore ◽  
Mimi Hughes ◽  
Kelly M. Mahoney ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Heat Fluxes ◽  
Back Trajectory ◽  
High Mountain ◽  
Wind Profiler ◽  
Plan View ◽  
Atmospheric Rivers ◽  
Tropical Water ◽  
Northeastern Pacific ◽  
The Impact

Abstract Atmospheric rivers (ARs) are a dominant mechanism for generating intense wintertime precipitation along the U.S. West Coast. While studies over the past 10 years have explored the impact of ARs in, and west of, California’s Sierra Nevada and the Pacific Northwest’s Cascade Mountains, their influence on the weather across the intermountain west remains an open question. This study utilizes gridded atmospheric datasets, satellite imagery, rawinsonde soundings, a 449-MHz wind profiler and global positioning system (GPS) receiver, and operational hydrometeorological observing networks to explore the dynamics and inland impacts of a landfalling, flood-producing AR across Arizona in January 2010. Plan-view, cross-section, and back-trajectory analyses quantify the synoptic and mesoscale forcing that led to widespread precipitation across the state. The analyses show that a strong AR formed in the lower midlatitudes over the northeastern Pacific Ocean via frontogenetic processes and sea surface latent-heat fluxes but without tapping into the adjacent tropical water vapor reservoir to the south. The wind profiler, GPS, and rawinsonde observations document strong orographic forcing in a moist neutral environment within the AR that led to extreme, orographically enhanced precipitation. The AR was oriented nearly orthogonal to the Mogollon Rim, a major escarpment crossing much of central Arizona, and was positioned between the high mountain ranges of northern Mexico. High melting levels during the heaviest precipitation contributed to region-wide flooding, while the high-altitude snowpack increased substantially. The characteristics of the AR that impacted Arizona in January 2010, and the resulting heavy orographic precipitation, are comparable to those of landfalling ARs and their impacts along the west coasts of midlatitude continents.

scholarly journals Oxygen depletion in subarctic peatland thaw lakes

2017 ◽  
Vol 3 (2) ◽  
pp. 406-428 ◽  
Author(s):  
Bethany N. Deshpande ◽  
Frédéric Maps ◽  
Alex Matveev ◽  
Warwick F. Vincent
Keyword(s):  
Dissolved Oxygen ◽  
Ice Cover ◽  
Oxygen Depletion ◽  
Freshwater Ecosystems ◽  
In Situ Sensors ◽  
Modelling Studies ◽  
Bottom Waters ◽  
Bacterial Decomposition ◽  
Permafrost Thawing ◽  
Thaw Lakes

Permafrost thawing and erosion results in the enrichment of northern lakes by soil organic matter. These allochthonous inputs favour bacterial decomposition and may cause the draw-down of dissolved oxygen to anoxic conditions that promote methanogenesis. Our objective in the present study was to determine the seasonal variations in dissolved oxygen in a set of permafrost peatland lakes in subarctic Quebec, Canada, and to relate these changes to metabolic rates, ice cover, and mixing. The lakes had high dissolved organic carbon concentrations, and their surface waters in summer had greenhouse gas concentrations that were up to one (CO2) to three (CH4) orders of magnitude above air-equilibrium values, indicating their strongly heterotrophic character. Consistent with these observations, the peatland lakes had elevated rates of bacterial production and oxygen consumption. Continuous measurements of oxygen by in situ sensors and of ice cover by automated field cameras showed that the lakes became fully anoxic shortly after freeze-up. The waters were partially re-oxygenated by mixing events in spring and fall, but in one lake, the bottom waters remained anoxic throughout the year. These observations provide a foundation for subsequent biogeochemical and modelling studies of peatland thaw lakes as an abundant class of Arctic freshwater ecosystems.

scholarly journals Observing Snow Cover and Water Resource Changes in the High Mountain Asia Region in Comparison with Global Mountain Trends over 2000–2018

2020 ◽  
Vol 12 (23) ◽  
pp. 3913
Author(s):  
Claudia Notarnicola
Keyword(s):  
Water Resources ◽  
Confidence Interval ◽  
Snow Cover ◽  
Water Storage ◽  
High Mountain ◽  
Global Level ◽  
Total Water ◽  
Mountain Areas ◽  
Snow Cover Extent ◽  
The Impact

The quantification of snow cover changes and of the related water resources in mountain areas has a key role for understanding the impact on several sectors such as ecosystem services, tourism and energy production. By using NASA-Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2000 to 2018, this study analyzes changes in snow cover in the High Mountain Asia region and compares them with global mountain areas. Globally, snow cover extent and duration are declining with significant trends in around 78% of mountain areas, and the High Mountain Asia region follows similar trends in around 86% of the areas. As an example, Shaluli Shan area in China shows significant negative trends for both snow cover extent and duration, with −11.4% (confidence interval: −17.7%, −5.5%) and −47.3 days (confidence interval: −70.4 days, −24.4 days) at elevations >5500 m a.s.l. respectively. In spring, an earlier snowmelt of −13.5 days (confidence interval: −24.3 days, −2.0 days) in 4000–5500 m a.s.l. is detected. On the other side, Tien Shan area shows an earlier snow onset of −28.8 days (confidence interval: −44.3 days, −8.2 days) between 2500 and 4000 m a.s.l., governed by decreasing temperature and increasing snowfall. In the current analysis, the Tibetan Plateau shows no significant changes. Regarding water resources, by using Gravity Recovery and Climate Experiment (GRACE) data it was found that around 50% of areas in the High Mountain Asia region and 30% at global level are suffering from significant negative temporal trends of total water storage (including groundwater, soil moisture, surface water, snow, and ice) in the period 2002–2015. In the High Mountain Asia region, this negative trend involves around 54% of the areas during spring period, while at a global level this percentage lies between 25% and 30% for all seasons. Positive trends for water storage are detected in a maximum 10% of the areas in High Mountain Asia region and in around 20% of the areas at global level. Overall snow mass changes determine a significant contribution to the total water storage changes up to 30% of the areas in winter and spring time over 2002–2015.

scholarly journals Effects of ground freezing and snow avalanche deposits on debris flows in alpine environments

2004 ◽  
Vol 4 (4) ◽  
pp. 519-530 ◽  
Author(s):  
E. Bardou ◽  
R. Delaloye
Keyword(s):  
Debris Flows ◽  
Soil Aggregates ◽  
Base Flow ◽  
Slope Instability ◽  
Snow Avalanche ◽  
Extreme Weather Events ◽  
Precipitation Event ◽  
High Mountain ◽  
Ground Freezing ◽  
The Impact

Abstract. Debris flows consist of a mixture of water and sediments of various sizes. Apart from few exceptions, the water is usually contributed directly from precipitation. In a high mountain environment like the Alps, it appears necessary to consider infiltration of water into the ground during rainfall events, the runoff characteristics and the potential supply of sediment as a function of a multitude of climatic and hydrogeological factors. This paper outlines several new processes - either linked to ice formation in the ground before an event, or to the presence of snow avalanche deposits - that change the probability of observing an event. These processes were identified during field observations connected with extreme weather events that occurred recently in the Valais Alps (south-western Switzerland): they can be seen as factors either amplifying or reducing the potential of slope instability caused by the precipitation event. An intense freezing of the ground during the week preceding the exceptional rainfall event in mid-October 2000 amplified the probability of triggering debris flows between roughly 1800 and 2300m asl. Both growth of ice needles and superficial ground freezing destroyed soil aggregates (increasing the availability of sediments) and/or, a deeper ground freezing resulted in decreased infiltration rate (increased runoff) during the first hours of heavy rainfall. The presence of snow avalanche deposits in a gully could be simultaneously an amplifying factor (the snow deposits increase the base flow and create a sliding plane for the sediments, mainly at the time of summer storms) or a reducing factor (reduction in the impact energy of the raindrops, mainly at the time of winter storms) of the risk of triggering debris flows. If it is not currently possible to establish rainfall threshold values for debris flow triggering, the knowledge and the implementation of these processes in the analysis of the potential triggering (for example by comparing the catchment hypsometric curve with the meteo-climatic situation) would nevertheless make the analysis of debris flows and forecasting more efficient.

scholarly journals Radiocarbon in the Air of Central Europe: Long-Term Investigations

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 823-834 ◽  
Author(s):  
I Svetlik ◽  
P P Povinec ◽  
M Molnár ◽  
M Vána ◽  
A Šivo ◽  
...  
Keyword(s):  
Central Europe ◽  
Monitoring Station ◽  
High Mountain ◽  
The Czech Republic ◽  
Suess Effect ◽  
Clean Air ◽  
Low Altitude ◽  
The Impact ◽  
Monitoring Stations

Regional levels of radiocarbon have been monitored in order to investigate the impact of fossil fuel combustion on the activity of atmospheric 14CO2 in central Europe. Data from atmospheric 14CO2 monitoring stations in the Czech Republic, Slovakia, and Hungary for the period 2000–2008 are presented and discussed. The Prague and Bratislava monitoring stations showed a distinct local Suess effect when compared to the Jungfraujoch clean-air monitoring station. However, during the summer period, statistically insignificant differences were observed between the low-altitude stations and the high-mountain Jungfraujoch station. 14C data from the Hungarian monitoring locality at Dunaföldvár and the Czech monitoring station at Košetice, which are not strongly affected by local fossil CO2 sources, indicate similar grouping and amplitudes, typical for a regional Suess effect.

Recent Atmospheric Variability at Kibo Summit, Kilimanjaro, and Its Relation to Climate Mode Activity

2018 ◽  
Vol 31 (10) ◽  
pp. 3875-3891 ◽  
Author(s):  
Emily Collier ◽  
Thomas Mölg ◽  
Tobias Sauter
Keyword(s):  
Indian Ocean ◽  
Current Knowledge ◽  
Southern Oscillation ◽  
Strong Association ◽  
Atmospheric Modeling ◽  
High Mountain ◽  
Atmospheric Variability ◽  
Rain Season ◽  
The Indian Ocean ◽  
The Impact

Abstract Accurate knowledge of the impact of internal atmospheric variability is required for the detection and attribution of climate change and for interpreting glacier records. However, current knowledge of such impacts in high-mountain regions is largely based on statistical methods, as the observational data required for process-based assessments are often spatially or temporally deficient. Using a case study of Kilimanjaro, 12 years of convection-permitting atmospheric modeling are combined with an 8-yr observational record to evaluate the impact of climate oscillations on recent high-altitude atmospheric variability during the short rains (the secondary rain season in the region). The focus is on two modes that have a well-established relationship with precipitation during this season, El Niño–Southern Oscillation and the Indian Ocean zonal mode, and demonstrate their strong association with local and mesoscale conditions at Kilimanjaro. Both oscillations correlate positively with humidity fluctuations, but the association is strongest with the Indian Ocean zonal mode in the air layers near and above the glaciers because of changes in zonal circulation and moisture transport, emphasizing the importance of the moisture signal from this basin. However, the most anomalous conditions are found during co-occurring positive events because of the combined effects of the (i) extended positive sea surface temperature anomalies, (ii) enhanced atmospheric moisture capacity from higher tropospheric temperatures, (iii) most pronounced weakening of the subsiding branch of the Indian Ocean Walker circulation over East Africa, and (iv) stronger monsoonal moisture fluxes upstream from Kilimanjaro. This study lays the foundation for unraveling the contribution of climate modes to observed changes in Kilimanjaro’s glaciers.

Relationship between atmospheric BC concentration and vehicular traffic in high mountain locations, case of study: Portillo, Chilean Central Andes

2020 ◽  
Author(s):  
Maria Florencia Ruggeri ◽  
Victor Vidal ◽  
Francisco Cereceda-Balic
Keyword(s):  
Climate Change ◽  
Seasonal Pattern ◽  
Early Morning ◽  
Central Andes ◽  
Traffic Density ◽  
High Mountain ◽  
Mountain Range ◽  
Vehicular Traffic ◽  
Mitigation And Adaptation ◽  
The Impact

&lt;p&gt;Black carbon (BC) has been pointed as the second largest contributor to climate change after greenhouse gases due to its superior ability to absorb solar radiation. This characteristic is particularly relevant in cryospheric environments, where the presence of BC has been related to a decrease in the albedo of ice/snow surfaces and the acceleration of their melting. In this sense, determination and quantification of BC levels in remote areas can be useful when defining and differentiating emission sources from which they come, considering the importance that the resources of the cryosphere mean for the surrounding populations for drinking water supply, agriculture, hydropower, mining, etc.&lt;/p&gt;&lt;p&gt;In this work, measurements of atmospheric BC from August 2016 to November 2019, carried out in Portillo, Chilean Central Andes, in the &quot;Nunatak&quot; laboratory-refuge (32&amp;#176;50&amp;#8217;43&amp;#8217;&amp;#8217;S, 70&amp;#176;07&amp;#8217;47&amp;#8217;&amp;#8217;W, 3000 m.a.s.l) are presented. This site, located in the highest altitude sector of the Andes mountain range, is very close to &amp;#8220;Los Libertadores&amp;#8221;, the border between Chile and Argentina. The road connecting both countries has a very high traffic density, with many passenger cars and trucks traveling in both directions. Due to weather, this route has a seasonal operating schedule. During the austral summer (September 1 - May 31) vehicular traffic is allowed 24 hours a day, while in winter (June 1 - August 31) traffic is allowed only from 8 am to 8 pm. Additionally, during heavy snowfalls, the access for vehicles is banned. To establish the impact of vehicular traffic on the atmospheric BC levels in the area, BC concentrations were continuously monitored by a Multi-Angle Absorption Photometer (MAAP) (Model 5012, Thermo). BC was measured in PM2.5, sampled on a glass filter tape an inlet air flow of 1.0 m&lt;sup&gt;3&lt;/sup&gt; h&lt;sup&gt;&amp;#8722;1&lt;/sup&gt;. Measurements were based on the optical attenuation at a wavelength of 637 nm. Data were originally sampled in one-minute resolution, but hourly and monthly means were extracted for further analysis. Results showed a markedly seasonal profile. Summer months presented the highest levels of BC for all the studied years, when the max. values were observed during the night and early morning hours, reaching 2.1 &amp;#181;g m&lt;sup&gt;-3&lt;/sup&gt;. In turn, during the day there were significant declines in BC concentrations, with min. BC values of 0.2 &amp;#181;g m&lt;sup&gt;-3&lt;/sup&gt;. Conversely, for all the years studied, winter months had lower average BC values than the summer months, with a markedly different hourly profile, since the max. values (up to 1.7 &amp;#181;g m&lt;sup&gt;-3&lt;/sup&gt;) were reached in noon and afternoon hours, while the min. values fell up to 0.1 &amp;#181;g m&lt;sup&gt;-3&lt;/sup&gt; during night and early morning hours. Furthermore, BC concentration levels in Portillo were measured at an altitude where the main glaciers of central Andes are, showing the impact that BC could cause in the nearby glaciers. This marked seasonal pattern is in line with the traffic operational schedule above-mentioned, suggesting that in the study area, vehicular traffic is the main emission source of atmospheric BC. These findings are key pieces to identifying and implementing successful strategies for mitigation and adaptation on climate change.&lt;/p&gt;

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