Isotope-age-dating of alpine spring water and global change : Evidence from temperature, chemistry and tritium data

Author(s):  
Martin Kralik ◽  
Erika Papp

<p>Global air-temperature changes over the last 150 years and in particular during the last 30 – 40 years are well documented world-wide. In alpine areas in Europe the increase in air-temperature is even higher in the range of 2° C. Very few studies exist about groundwater temperature changes due to global warming. The increase or decrease in temperature at the point of discharge depends besides the air temperature at the time of infiltration on the amount of precipitation, the local meteorological conditions, the mean residence time, the land use, and the natural and anthropogenic heat flow during the passage underground.</p><p>Nearly no papers exist about the water quality changes due to global change impacts and Mean Residence Times (MRT). This is very difficult to evaluate due to missing long-term quality measurements and strong impacts by anthropogenic activities and land use changes. To avoid the complication by anthropogenic land use changes and activities the authors investigated the on-line discharge, temperature, and electric conductivity measurements as well as quarterly hydro-chemical and isotope analyses of 40 Alpine springs from a monitoring network all over the Austrian Alps (approx. 60,000 km<sup>2</sup>). All the selected springs have a recharge area with no or minimal anthropogenic impacts during the last 30 – 40 years. About 235,000 on-line measurements and 11,000 chemical analyses were evaluated for trends and compared to daily measurements at meteorological and surface water stations close to the recharge areas of the springs. To show the connection to the paleoclimatology changes of existing δ<sup>18</sup>O measurements on precipitation and spring water was evaluated as well indicating altitudes of recharge areas in range of 500 – 2400m.</p><p>Forty springs with a minimum record of 16 years have been selected for trend analysis over a period of 20 years (1993 – 2013). 28 (74%) of the selected spring show a significant mean increase in water temperature of 0.34 °C in the range of 0.06 to 1.03 °C. This increase is half of the air- and water temperature increase in meteorological stations and surface waters close to the recharge areas of the investigated springs. The electric conductivity linearly increased in 21 (55%) of the investigated springs at about 4%. The discharge stayed the same in most springs. In 23 (72%) springs the content of dissolved oxygen decreased over these 20 years at about 9% percent.</p><p>The reasons of the changes in water-temperature, dissolved load and the oxygen content as well as the impact of different Mean Residence Times (MRT) will be discussed and interpreted.</p>

2004 ◽  
Vol 8 (1) ◽  
pp. 108-114 ◽  
Author(s):  
W. Buytaert ◽  
B. De Bièvre ◽  
G. Wyseure ◽  
J. Deckers

Abstract. The high Andes region of South Ecuador (The Páramo) is characterised by a cold and wet climate. Most soils of the Páramo region are Andosols and Histosols, with a very high water retention capacity that is affected irreversibly by drying. This key property of Páramo soils buffers catchment outflow, resulting in an almost uniform outflow pattern which, notwithstanding the variability in rainfall, can be very variable in space and time. These soils serve as the most important reservoir of drinking and irrigation water for the densely populated inter-Andean depression region. The Páramo has long served only as an extensive grazing area but recent population pressure and land scarcity have increased cultivation. Two small Páramo catchments (about 2 km2) were monitored intensively for precipitation and discharge for over a year to assess the effect of such land-use changes on the hydrological properties. One catchment is in an undisturbed area and grazed intensively while in the other, local farmers started intensive drainage for cultivation of potatoes about five years ago. The linear reservoir concept has been used to assess the overall retention capacity of the catchments in terms of both peak response and base flow. In this model, every catchment is considered as a series of independent parallel reservoirs, each characterised by mean residence times (T). In every catchment, three major mean residence times can be distinguished. In the undisturbed catchment, an immediate response, characterised by a T of 5.4 hours, is followed by a slower response with a T of 44.3 h. The base flow has a mean T value of 360 h. The response of the cultivated catchment is similar with T values of 3.6 h, 27.2 h and 175 h, respectively. As a result, in the disturbed catchment, water release is about 40% faster than in the undisturbed catchment, so that the base flow falls rapidly to lower levels. The linear reservoir model is a simple way of quantifying the impact of land use changes on the water regulation capacity of Páramo catchments. Keywords: linear reservoir, Páramo, mountain hydrology, land use changes, Ecuador


2006 ◽  
Vol 19 (12) ◽  
pp. 2763-2782 ◽  
Author(s):  
Peter A. Stott ◽  
Gareth S. Jones ◽  
Jason A. Lowe ◽  
Peter Thorne ◽  
Chris Durman ◽  
...  

Abstract The ability of climate models to simulate large-scale temperature changes during the twentieth century when they include both anthropogenic and natural forcings and their inability to account for warming over the last 50 yr when they exclude increasing greenhouse gas concentrations has been used as evidence for an anthropogenic influence on global warming. One criticism of the models used in many of these studies is that they exclude some forcings of potential importance, notably from fossil fuel black carbon, biomass smoke, and land use changes. Herein transient simulations with a new model, the Hadley Centre Global Environmental Model version 1 (HadGEM1), are described, which include these forcings in addition to other anthropogenic and natural forcings, and a fully interactive treatment of atmospheric sulfur and its effects on clouds. These new simulations support previous work by showing that there was a significant anthropogenic influence on near-surface temperature change over the last century. They demonstrate that black carbon and land use changes are relatively unimportant for explaining global mean near-surface temperature changes. The pattern of warming in the troposphere and cooling in the stratosphere that has been observed in radiosonde data since 1958 can only be reproduced when the model includes anthropogenic forcings. However, there are some discrepancies between the model simulations and radiosonde data, which are largest where observational uncertainty is greatest in the Tropics and high latitudes. Predictions of future warming have also been made using the new model. Twenty-first-century warming rates, following policy-relevant emissions scenarios, are slightly greater in HadGEM1 than in the Third Hadley Centre Coupled Ocean–Atmosphere General Circulation Model (HadCM3) as a result of the extra forcing in HadGEM1. An experiment in which greenhouse gases and other anthropogenic forcings are stabilized at 2100 levels and held constant until 2200 predicts a committed twenty-second-century warming of less than 1 K, whose spatial distribution resembles that of warming during the twenty-first century, implying that the local feedbacks that determine the pattern of warming do not change significantly.


2014 ◽  
Vol 5 (1) ◽  
pp. 281-326 ◽  
Author(s):  
R. J. van der Ent ◽  
L. Wang-Erlandsson ◽  
P. W. Keys ◽  
H. H. G. Savenije

Abstract. The contribution of land evaporation to local and remote precipitation (i.e., moisture recycling) is of significant importance to sustain water resources and ecosystems. But how important are different evaporation components in sustaining precipitation? This is the first paper to present moisture recycling metrics for partitioned evaporation. In the companion paper, Part 1, evaporation was partitioned into vegetation interception, floor interception, soil moisture evaporation and open water evaporation (constituting the direct, purely physical fluxes, largely dominated by interception), and transpiration (delayed, biophysical flux). Here, we track these components forward as well as backward in time. We also include age tracers to study the atmospheric residence times of these evaporation components. As the main result we present a new image of the global hydrological cycle that includes quantification of partitioned evaporation and moisture recycling as well as the atmospheric residence times of all fluxes. We demonstrate that evaporated interception is more likely to return as precipitation on land than transpired water. On average, direct evaporation (essentially interception) is found to have an atmospheric residence time of eight days, while transpiration typically resides nine days in the atmosphere. Interception recycling has a much shorter local length scale than transpiration recycling, thus interception generally precipitates closer to its evaporative source than transpiration, which is particularly pronounced outside the tropics. We conclude that interception mainly works as an intensifier of the local hydrological cycle during wet spells. On the other hand, transpiration remains active during dry spells and is transported over much larger distances downwind where it can act as a significant source of moisture. Thus, as various land-use types can differ considerably in their partitioning between interception and transpiration, our results stress that land-use changes (e.g., forest to cropland conversion) do not only affect the magnitude of moisture recycling, but could also influence the moisture recycling patterns and lead to a redistribution of water resources. As such, this research highlights that land-use changes can have complex effects on the atmospheric branch of the hydrological cycle.


Author(s):  
Risya Lailarahma ◽  
I Wayan Sandi Adnyana

Land use changes over Jakarta caused by urbanization affected the increasing of infrastructure and decreasing vegetation from 2003 to 2016. This condition reduced water infiltration and caused inundation when heavy rainfall coming. Then Aedes aegypti would breed.and increased which brought dengue fever desease. This study was about analyzing the land use change in Jakarta Province using Landsat image, and its relationship with land surface temperature and dengue fever distribution. The effects of land use change also analysed by this study which including the effects from temperature and dengue fever that analysed by indices of land use in Jakarta at 2003 and 2016. The temperature analysis could be obtained by TIR band in Landsat and using some algortitma which calculated in band math of ENVI software. Vegetation index value’s average decreased from 0.652 in 2003 to 0.647 2016 in 2016. Built up index value’s average increased from -0.03 in 2003 to -0.02 in 2016. While Bareland index value’s average decreased from 0.16 in 2003 to -0.46 in 2016. Land surface temperature increased 3?C from 2003 to 2016. Vegetation area decreased 27.929 ha, bare land area decreased 6.012 ha, while built up area increased 34.278 ha from 2003 to 2016. Increasing of land surface temperature proportional to increasing dengue fever patients 1.187 patients. Increasing of land surface temperature increasing dengue fever cases 1.187 patients. To review and monitor more about the relationship between landuse changes and temperature changes required image with high resolution so that the results obtained more accurate. Complete data of dengue fever per subdistricts also required to analyse further more about relationship between landuse changes, temperature changes, and dengue fever.


2014 ◽  
Vol 5 (2) ◽  
pp. 471-489 ◽  
Author(s):  
R. J. van der Ent ◽  
L. Wang-Erlandsson ◽  
P. W. Keys ◽  
H. H. G. Savenije

Abstract. The contribution of land evaporation to local and remote precipitation (i.e. moisture recycling) is of significant importance to sustain water resources and ecosystems. But how important are different evaporation components in sustaining precipitation? This is the first paper to present moisture recycling metrics for partitioned evaporation. In the companion paper Wang-Erlandsson et al. (2014) (hereafter Part 1), evaporation was partitioned into vegetation interception, floor interception, soil moisture evaporation and open-water evaporation (constituting the direct, purely physical fluxes, largely dominated by interception), and transpiration (delayed, biophysical flux). Here, we track these components forward as well as backward in time. We also include age tracers to study the atmospheric residence times of these evaporation components. We present a new image of the global hydrological cycle that includes quantification of partitioned evaporation and moisture recycling as well as the atmospheric residence times of all fluxes. We demonstrate that evaporated interception is more likely to return as precipitation on land than transpired water. On average, direct evaporation (essentially interception) is found to have an atmospheric residence time of 8 days, while transpiration typically resides for 9 days in the atmosphere. The process scale over which evaporation recycles is more local for interception compared to transpiration; thus interception generally precipitates closer to its evaporative source than transpiration, which is particularly pronounced outside the tropics. We conclude that interception mainly works as an intensifier of the local hydrological cycle during wet spells and wet seasons. On the other hand, transpiration remains active during dry spells and dry seasons and is transported over much larger distances downwind, where it can act as a significant source of moisture. Thus, as various land-use types can differ considerably in their partitioning between interception and transpiration, our results stress that land-use changes (e.g. forest-to-cropland conversion) do not only affect the magnitude of moisture recycling, but could also influence the moisture recycling patterns and lead to a redistribution of water resources. As such, this research highlights that land-use changes can have complex effects on the atmospheric branch of the hydrological cycle.


2020 ◽  
Author(s):  
Ivan Vasenev ◽  
Tatyana Komarova ◽  
Solomon Melese

<p><strong>Introduction.</strong> Natural reforestation is the widespread trend in the modern land-use changes in the southern taiga zone at the European territory of Russia after 1990s. Its total area is more than 10 million ha. At the same time forest natural regeneration is mutual usual process in the long-term land-use changes in this part of Russia with complex history of its development during millennium. It plays crucial role in soil successions, their fertility and environmental function dynamics including bio productivity support and carbon sequestration, which is given special attention against the background of global climate change challenges in the twenty-first century. This paper presents the results of a round-the-year monitoring of soil CO<sub>2</sub> emission in comparable sites of the fallow lands chrono sequences in conditions of a representative area of the Central Forest Reserve with background wood-sorrel spruce forests which are typical for the southern taiga zone of Central Russia.</p><p><strong>Objects and methods. </strong>The dominant soil type is sandy-loam Albeluvisols (by WRB, or Orthopodzolic soil by Russia Taxonomy, or Alfisols by Soil Taxonomy, or Podzoluvisols by FAO). The studies have been done in the representative 5 sites at different age of natural reforestation: (1) Fallow meadow grassland – “0-moment”; (2) Forest-fallow birch domination stage of 10-15 year; (3) Birch domination stage of 20-30 year with young spruce participation; (4) Birch-forest stage of 50-60 year with spruce participation; (5) Spruce-forest after fallow stage of more than 100 year with birch participation. CO<sub>2</sub> fluxes seasonal and diurnal dynamics measuring were carried out in situ using a mobile gas analyzer Li-820 and soil exposure chambers with parallel measurements of air temperature, soil temperature and moisture. Also, biomass, soil organic carbon and bulk density were analyzed in their topsoil and subsoil horizons with C stock calculation.</p><p><strong>Results and discussion.</strong> Analysis of the successional dynamics of the topsoil organic carbon stock showed the maximum rate of their increasing in the first stages of natural reforestation by a thick undergrowth of birch (more than 30 g m<sup>-2</sup>∙year<sup>-1</sup>) that agrees well with the maximum intensity of the woody biomass growth in case of dominant birch forest up to 50-60 years (more than 100 g m<sup>-2</sup>∙year<sup>-1</sup>). Research revealed the maximum intensity of soil CO<sub>2</sub> emission (up to 11-12 g C-CO<sub>2</sub> m<sup>-2</sup>∙day<sup>-1</sup>) in the meadow fallow land and its gradual decreasing in process of reforestation down to values close to background ecosystems in 4-5 g C-CO<sub>2</sub> m<sup>-2</sup>∙day<sup>-1 </sup>in the last investigated succession study with wood-sorrel spruce older than 100 years, which is in good correlation with the gradual humus accumulation in topsoil due to reduced mineralization of organic compounds from dying vegetation. The seasonal and daily dynamics of soil CO<sub>2</sub> emissions are determined by soil temperature (K<sub>TS</sub> 0.77 - 0.99), air temperature (K<sub>TA</sub> 0.42 - 0.99), and soil moisture in spring and fall (K<sub>WS</sub> -0.55 - -0.98).</p><p><strong>Conclusions. </strong>Investigation of forest natural regeneration impacts on the level of soil organic carbon accumulation and CO<sub>2</sub> fluxes in the representative southern taiga ecosystems is important element of their soil environmental monitoring and management.</p>


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1916
Author(s):  
Yuchuan Lai ◽  
David A. Dzombak

Drinking water distribution systems (DWDS) are affected by climate change and this work aimed to assess the effect of changing ambient air temperature on the water temperature and various water quality parameters in DWDS. A water temperature estimation model was identified and evaluated at seven specific locations in the U.S. and water quality parameters were assessed with a case study for Washington D.C. Preliminary estimation of changes in water temperature and two temperature-related parameters (the chlorine decay rate and bacterial activity) were developed for 91 U.S. cities using local air temperature observations and projections. Estimated water temperature changes in DWDS are generally equivalent to air temperature changes on an annual average basis, suggesting modest changes for the assessed historical periods and possibly more intensified changes in the future with greater increase in air temperature. As higher water age can amplify the temperature effect and the effects of temperature on some water quality parameters can be inter-related, yielding an aggregated effect, evaluation of extreme cases for DWDS will be of importance. In responding to changing climate conditions, assessments of DWDS water temperature changes and resulting impacts on water quality merit more attention to ensure appropriate adaptation of DWDS design and management.


Author(s):  
A. Baloloy ◽  
R. R. Sta. Ana ◽  
J. A. Cruz ◽  
A. C. Blanco ◽  
N. V. Lubrica ◽  
...  

Abstract. Urbanization can be observed through the occurrence of land-use changes as more land is being transformed and developed for urban use. One of the Philippine cities with high rate of urbanization is Baguio City, known for having a subtropical highland climate. To understand the spatiotemporal relationship between urbanization and temperature, this study aims to analyze the correlation of urban extent with land surface and air temperature in Baguio City using satellite-based built-up extents, land surface temperature (LST) maps, and weather station-recorded air temperature data. Built-up extent layers were derived from three satellite images: Landsat, RapidEye and PlanetScope. Land-use land cover (LULC) maps were generated from Landsat images using biophysical indices such as Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI); while RapidEye and PlanetScope built-up extent maps were generated by applying the visible green-based built-up index (VgNIR-BI). Mean LST values from 1988 to 2018 during the dry and wet seasons were calculated from the Landsat-retrieved surface temperature layers. The result of the study shows that the increase in the built-up extent significantly intensified the LST during the dry season which was observed in all satellite data-derived built-up maps: RapidEye+PlanetScope (2012–2018; r = 0.88), Landsat 8 (2012–2018; r = 0.63) and Landsat 5,7,8 (1988–2018; r = 0.61). The main LST hotspots were detected inside the Central Business District where it expanded gradually from year 1998 (43 ha) to 2011 (83 ha), but have increased extensively within the years 2014 to 2019 (305 ha). On average, 98.5% of the hotspots detected from 1995 to 2019 are within the equivalent built-up area.


<em>Abstract.</em>—Relatively little information is available regarding the environmental factors influencing water temperature in streams draining low-elevation, glaciated landscapes in the upper Midwest. We used multiple regression analysis and covariance structure analysis (CSA) to identify the landscape features that influence spatial variation in mean July water temperature in 282 lower Michigan stream sites and to determine the spatial scales over which these features operate. Both modeling approaches explained from 63% to 65% of the spatial variation in stream temperatures and suggested that thermal regimes in lower Michigan are influenced by a suite of landscape factors operating at catchment and local scales. However, CSA, because it incorporated both direct and indirect effects, provided a more robust approach for identifying the relative influence of landscape features on stream temperature. Our CSA model suggested that catchment area, latitude, local groundwater inputs, local forest cover, air temperature, percent catchment agriculture, percent catchment lakes and wetlands, and percent catchment coarse-textured geology were important factors structuring spatial variation in stream temperatures. Our analysis also suggested that impacts on stream temperature from land cover/ land use changes are of similar or greater magnitude as those resulting from increases in air temperature associated with global climate warming.


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