scholarly journals Hydrogeochemical Responses of Cave Drip Water to the Local Climate in Liangfeng Cave, Southwest China

2021 ◽  
Author(s):  
Xia Wu ◽  
Moucheng Pan ◽  
Meiliang Zhang ◽  
Jianhua Cao
Keyword(s):  
Southwest China ◽  
Regional Climate ◽  
Climate Data ◽  
Environmental Index ◽  
Local Climate ◽  
Drip Water ◽  
Cave Drip Water ◽  
The Difference ◽  
High Precipitation ◽  
Liangfeng Cave

Abstract The hydrogeochemistry of cave drip water is an important environmental index in cave systems, and drip water monitoring may be an essential solution for paleoclimate reconstructions. We measured the hydrogeochemical properties of the seasonal and perennial drip water and CO2 concentrations from 2015 to 2019 in Liangfeng Cave, Guilin, Southwest China. This study identified the difference in the regional environmental records in perennial and seasonal drip water. By comparing the regional climate data recorded by the drip water, the results showed the perennial drip water recorded regional climate information throughout the year, while the seasonal drip water only recorded the high precipitation periods. The precipitation during the 2015 dry season was abnormally high, which not sure what index is higher than the values in other rainy seasons. This indicates that hydrogeochemistry only represents changes in precipitation and not the alternation of dry and rainy seasons during this period.

scholarly journals Explaining mass balance and retreat dichotomies at Taku and Lemon Creek Glaciers, Alaska

2020 ◽  
Vol 66 (258) ◽  
pp. 530-542 ◽  
Author(s):  
Christopher McNeil ◽  
Shad O'Neel ◽  
Michael Loso ◽  
Mauri Pelto ◽  
Louis Sass ◽  
...  
Keyword(s):  
Mass Balance ◽  
Average Rate ◽  
Regional Climate ◽  
Strong Correlations ◽  
Climate Data ◽  
Negative Mass ◽  
Regional Warming ◽  
Local Climate ◽  
Surface Mass ◽  
Cumulative Mass

AbstractWe reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. Over the 1946–2018 period, the cumulative mass balances diverged. Tidewater Taku Glacier advanced and gained mass at an average rate of +0.25 ± 0.28 m w.e. a–1, contrasting with retreat and mass loss of −0.60 ± 0.15 m w.e. a−1 at land-terminating Lemon Creek Glacier. The uniform influence of regional climate is demonstrated by strong correlations among annual mass balance and climate data. Regional warming trends forced similar statistically significant decreases in surface mass balance after 1989: −0.83 m w.e. a–1 at Taku Glacier and −0.81 m w.e. a–1 at Lemon Creek Glacier. Divergence in cumulative mass balance arises from differences in glacier hypsometry and local climate. Since 2013 negative mass balance and glacier-wide thinning prevailed at Taku Glacier. These changes initiated terminus retreat, which could increase dramatically if calving begins. The future mass balance trajectory of Taku Glacier hinges on dynamics, likely ending the historic dichotomy between these glaciers.

scholarly journals Circumferential and Longitudinal δ13C Variability in a Larix decidua Trunk from the Swiss Alps

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 117 ◽  
Author(s):  
Jan Esper ◽  
Dana F.C. Riechelmann ◽  
Steffen Holzkämper
Keyword(s):  
Tree Ring ◽  
Regional Climate ◽  
Tree Height ◽  
Vertical Gradient ◽  
Larix Decidua ◽  
Swiss Alps ◽  
Systematic Change ◽  
Climate Data ◽  
Δ13c Values ◽  
The Difference

Tree-ring stable isotopes are insightful proxies providing information on pre-instrumental climate fluctuations, yet the variability of these data within a tree trunk has not been fully explored. Here, we analyze longitudinal and circumferential changes in tree-ring δ13C values from 1991–2010, considering seven height levels from 1 to 13 m above ground and six sampling directions (radii) separated by 60° around the stem. The disk samples were taken from a 360-year old European larch (Larix decidua Mill.) that grew at 1675 m above sea level in the Simplon Valley, Switzerland. Results show that the circumferential δ13C variability, defined as the difference between the minimum and maximum isotope values within a single ring at a certain height, ranges from 0.5 to 2.8‰. These differences appear substantial as they match the range of year-to-year variations retained in long tree-ring δ13C time series used for climate reconstruction. The assessment of longitudinal variability demonstrated a systematic change of ~0.1‰ m−1 towards isotopically heavier (less negative) δ13C values with increasing tree height, likely reflecting a vertical gradient towards isotopically heavier needle tissue due to changing microclimatic conditions and CO2 stratification within the canopy. Calibration against regional climate data indicates no substantial signal changes in δ13C values within the trunk. We conclude that the longitudinal isotope gradient adds uncertainty to long δ13C chronologies derived from subfossil material of unknown (and changing) sampling heights. The large circumferential variability recorded in the sub-alpine larch suggests that more than two cores are needed to analyze absolute δ13C values representative for each tree.

scholarly journals Temporal inventory of glaciers in the Suru sub-basin, western Himalaya: Impacts of the regional climate variability

2019 ◽  
Author(s):  
Aparna Shukla ◽  
Siddhi Garg ◽  
Manish Mehta ◽  
Vinit Kumar ◽  
Uma Kant Shukla
Keyword(s):  
Climate Variability ◽  
Regional Climate ◽  
Remote Sensing Data ◽  
Western Himalaya ◽  
Temporal Analysis ◽  
Mean Annual Temperature ◽  
Climate Data ◽  
Local Climate ◽  
Western Himalayan Region ◽  
Varied Response

Abstract. Updated knowledge about the glacier extent and characteristics in the Himalaya cannot be overemphasised. Availability of precise glacier inventories in the latitudinally diverse western Himalayan region is particularly crucial. In this study we have created an inventory of the Suru sub-basin, western Himalaya for year 2017 using Landsat OLI data. Changes in glacier parameters have also been monitored from 1971 to 2017 using temporal satellite remote sensing data and limited field observations. Inventory data shows that the sub-basin has 252 glaciers covering 11 % of the basin, having an average slope of 25 ± 6° and dominantly north orientation. The average snow line altitude (SLA) of the basin is 5011 ± 54 masl with smaller (47 %) and cleaner (43 %) glaciers occupying the bulk area. Longterm climate data (1901–2017) shows an increase in the mean annual temperature (Tmin & Tmax) by 0.77 ºC (0.25 & 1.3 ºC) in the sub-basin, driving the overall glacier variability in the region. Temporal analysis reveals a glacier shrinkage of ~ 6 ± 0.02 %, an average retreat rate of 4.3 ± 1.02 ma−1, debris increase of 62 % and 22 ± 60 m SLA rise in past 46 years. This confirms their transitional response between the Karakoram and the Greater Himalayan Range (GHR) glaciers. Besides, glaciers in the sub-basin occupy two major ranges, i.e., GHR and Ladakh range (LR) and experience local climate variability, with the GHR glaciers exhibiting a warmer and wetter climate as compared to the LR glaciers. This variability manifestes itself in the varied response of GHR and LR glaciers. While the GHR glaciers exhibit an overall rise in SLA (GHR: 49 ± 69 m; LR: decrease by 18 ± 50 m), the LR glaciers have deglaciated more (LR: 7 %; GHR: 6 %) with an enhanced accumulation of debris cover (LR: 73 %; GHR: 59 %). Inferences from this study reveal prevalence of glacier disintegration and overall degeneration, transition of clean ice to partially debris covered glaciers, local climate variability and non-climatic (topographic and morphometric) factor induced heterogeinty in glacier response as the major processes operatives in this region. The dataset (Shukla et al., 2019) is accessible at https://doi.pangaea.de/10.1594/PANGAEA.904131.

scholarly journals Temporal inventory of glaciers in the Suru sub-basin, western Himalaya: impacts of regional climate variability

2020 ◽  
Vol 12 (2) ◽  
pp. 1245-1265 ◽  
Author(s):  
Aparna Shukla ◽  
Siddhi Garg ◽  
Manish Mehta ◽  
Vinit Kumar ◽  
Uma Kant Shukla
Keyword(s):  
Climate Variability ◽  
Regional Climate ◽  
Remote Sensing Data ◽  
Western Himalaya ◽  
Temporal Analysis ◽  
Mean Annual Temperature ◽  
Climate Data ◽  
Local Climate ◽  
Western Himalayan Region ◽  
Varied Response

Abstract. The importance of updated knowledge about the glacier extent and characteristics in the Himalaya cannot be overemphasized. Availability of precise glacier inventories in the latitudinally diverse western Himalayan region is particularly crucial. In this study we have created an inventory of the Suru sub-basin in the western Himalaya for the year 2017 using Landsat Operational Land Imager (OLI) data. Changes in glacier parameters have also been monitored from 1971 to 2017 using temporal satellite remote-sensing data and limited field observations. Inventory data show that the sub-basin has 252 glaciers covering 11 % of the basin, having an average slope of 25±6∘ (standard deviations have been italicized throughout the text) and dominantly north orientation. The average snow line altitude (SLA) of the basin is 5011±54 m a.s.l. with smaller (47 %) and cleaner (43 %) glaciers occupying the bulk area. Long-term climate data (1901–2017) show an increase in the mean annual temperature (Tmax⁡ and Tmin⁡) of 0.77 ∘C (0.25 and 1.3 ∘C) in the sub-basin, driving the overall glacier variability in the region. Temporal analysis reveals a glacier shrinkage of ∼6±0.02 %, an average retreat rate of 4.3±1.02 m a−1, debris increase of 62 % and a 22±60 m SLA increase in the past 46 years. This confirms their transitional response between the Karakoram and the Greater Himalayan Range (GHR) glaciers. Besides, glaciers in the sub-basin occupy two major ranges, the GHR and Ladakh Range (LR), and experience local climate variability, with the GHR glaciers exhibiting a warmer and wetter climate as compared to the LR glaciers. This variability manifests itself in the varied response of GHR and LR glaciers. While the GHR glaciers exhibit an overall rise in SLA (GHR: 49±69 m; LR: decrease of 18±50 m), the LR glaciers have deglaciated more (LR: 7 %; GHR: 6 %) with an enhanced accumulation of debris cover (LR: 73 %; GHR: 59 %). Inferences from this study reveal prevalence of glacier disintegration and overall degeneration, transition of clean ice to partially debris-covered glaciers, local climate variability and non-climatic (topographic and morphometric)-factor-induced heterogeneity in glacier response as the major processes operating in this region. The Shukla et al. (2019) dataset is accessible at https://doi.org/10.1594/PANGAEA.904131.

Buildings

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Energy Efficient ◽  
Energy Use ◽  
Fossil Fuel ◽  
Local Climate ◽  
Heating And Cooling ◽  
The Difference ◽  
As If

Most of the energy used by buildings goes into heating and cooling. For small buildings, such as houses, heat transfer by conduction through the sides is as much as, if not greater than, the heat transfer from air exchanges with the outside. For large buildings, such as offices and factories, the greater volume-to-surface ratio means that air exchanges are more significant. Lights, people and equipment can make significant contributions. Since the energy used depends on the difference in temperature between the inside and the outside, local climate is the most important factor that determines energy use. If heating is required, it is usually more efficient to use a heat pump than to directly burn a fossil fuel. Using diffuse daylight is always more energy efficient than lighting up a room with artificial lights, although this will set a limit on the size of buildings.

scholarly journals Urban Climates and Climate Change

2020 ◽  
Vol 45 (1) ◽  
pp. 411-444 ◽  
Author(s):  
Valéry Masson ◽  
Aude Lemonsu ◽  
Julia Hidalgo ◽  
James Voogt
Keyword(s):  
Climate Change ◽  
Climate Modeling ◽  
Regional Climate ◽  
Urban Climate ◽  
Regional Climate Modeling ◽  
Climate Impact ◽  
Local Climate ◽  
Urban Climatology ◽  
Recent Developments ◽  
Global Agenda

Cities are particularly vulnerable to extreme weather episodes, which are expected to increase with climate change. Cities also influence their own local climate, for example, through the relative warming known as the urban heat island (UHI) effect. This review discusses urban climate features (even in complex terrain) and processes. We then present state-of-the-art methodologies on the generalization of a common urban neighborhood classification for UHI studies, as well as recent developments in observation systems and crowdsourcing approaches. We discuss new modeling paradigms pertinent to climate impact studies, with a focus on building energetics and urban vegetation. In combination with regional climate modeling, new methods benefit the variety of climate scenarios and models to provide pertinent information at urban scale. Finally, this article presents how recent research in urban climatology contributes to the global agenda on cities and climate change.

scholarly journals Assessment of the Construction of a Climate Resilient City: An Empirical Study Based on the Difference in Differences Model

2021 ◽  
Vol 18 (4) ◽  
pp. 2082
Author(s):  
Zifeng Liang
Keyword(s):  
Significant Contribution ◽  
Evaluation Method ◽  
Regional Climate ◽  
Chinese Government ◽  
Infrastructure Development ◽  
Grey System ◽  
Difference In Differences ◽  
Climate Resilience ◽  
The Difference ◽  
The Impact

Facing climate risks has become a common problem for mankind and a topic of great importance for the Chinese government. To thoroughly implement the overall requirements for the construction of an ecological civilization and effectively improve the capacity of cities to adapt to climate change, China launched the pilot construction of “Climate Resilient Cities” in 2017. In this paper, 16 prefecture level cities in Anhui Province of China were selected as the research objects, and the multi-level grey system evaluation method was used to measure the climate resilience of these regions. We used the difference in differences method to evaluate the effect of the pilot policy of “Climate Resilient Cities.” The pilot policies of the “Climate Resilient Cities” showed a significant contribution to the regional climate resilience, and, after isolating the impact of other factors on the regional climate resilience, the pilot policies of the “Climate Resilient Cities” increased the climate resilience of the pilot cities by four percentage points. The pilot policies of the “Climate Resilient Cities” had a significant contribution to the urban infrastructure development and ecological space optimization, as well as non-significant impacts to the urban water security, emergency management capacity-building, and science and technology innovation initiatives.

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