Influence Of Non-climatic Factors Research Articles

Tree ring based drought variability in Northwest Tajikistan since 1895 AD

Determining the mechanisms controlling the changes of wet and dry conditions will improve our understanding of climate change over the past hundred years, which is of great significance to the study of climate and environmental changes in the arid regions of Central Asia. Forest trees are ecologically significant in the local environment, and therefore the tree ring analysis can provide a clear record of regional historical climate. This study analyzed the correlation between the tree ring width chronology of Juniperus turkestanica Komarov and the standardized precipitation evapotranspiration index (SPEI) in Northwest Tajikistan, based on 56 tree ring samples collected from Shahristan in the Pamir region. Climate data including precipitation, temperature and the SPEI were downloaded from the Climate Research Unit (CRU) TS 4.00. The COFECHA program was used for cross-dating, and the ARSTAN program was used to remove the growth trend of the tree itself and the influence of non-climatic factors on the growth of the trees. A significant correlation was found between the radial growth of J. turkestanica trees and the monthly mean SPEI of February–April. The monthly mean SPEI sequence of February–April during the period of 1895–2016 was reconstructed, and the reconstruction equation explained 42.5% of the variance. During the past 122 a (1895–2016), the study area has experienced three wetter periods (precipitation above average): 1901–1919, 1945–1983 and 1995–2010, and four drier periods (precipitation below average): 1895–1900, 1920–1944, 1984–1994 and 2011–2016. The spatial correlation analysis revealed that the monthly mean SPEI reconstruction sequence of February–April could be used to characterize the large-scale dry-wet variations in Northwest Tajikistan during the period of 1895–2016. This study could provide comparative data for validating the projections of climate models and scientific basis for managing water resources in Tajikistan in the context of climate change.

A meta-analysis of urban climate change adaptation planning in the U.S.

The concentration of people, infrastructure, and ecosystem services in urban areas make them prime sites for climate change adaptation. While advances have been made in the development of frameworks for adaptation planning and in identifying both real and potential barriers to action, empirical work evaluating urban adaptation planning processes has been relatively piecemeal. Existing assessments of current experience with urban adaptation provide necessarily broad generalizations based on the available peer-reviewed literature. This paper uses a meta-analysis of U.S. cities’ current experience with urban adaptation planning drawing from 54 sources that include peer-reviewed literature, government reports, white papers, and reports published by non-governmental organizations. The analysis specifically evaluates the institutional support structures being developed for urban climate change adaptation. The results demonstrate that adaptation planning is driven by a desire to reduce vulnerability and often catalyzes new collaborations and coordination mechanisms in urban governance. As a result, building capacity for urban climate change adaptation planning requires a focus not only on city governments themselves but also on the complex horizontal and vertical networks that have arisen around such efforts. Existing adaptation planning often lacks attention to equity issues, social vulnerability, and the influence of non-climatic factors on vulnerability. Engaging city governments and communities in adaptation planning – whether to initiate or expand such efforts – may require that adaptation planning is framed to capitalize on their motivation to protect assets and reduce vulnerability.

Influence of non-climatic factors on the relationships between tree growth and climate over the Chinese Loess Plateau

Modulations of non-climatic factors on climate–growth relationships can confound the interpretation of dendroclimatic reconstructions. Accordingly, we evaluated the influences of core direction, tree age, tree size, growth rate and species on the climate–growth relationships of 210 tree-ring cores from Kongtong Mountain and Xiaolong Mountain on the semi-arid Chinese Loess Plateau. We employed both the linear methods of correlation and response function analyses, and the nonlinear method of the Boosted Regression Trees (BRT). Most trees are sensitive to the moisture availability. Old trees are more sensitive to drought than young trees, which may be related to the intensified hydraulic resistances and reduced photosynthesis in response to drought. Tree cores taken from the southern direction are often more sensitive to drought than cores taken from other directions. The enhanced drought sensitivity for the southern cores may be possibly related to more branches and leaves for photosynthesis. Slow-growing trees show higher correlations with precipitation of the September prior to growth. This indicates that the extremely stressed, slow-growing trees tend to rely largely on nutrients produced prior to the growing season. For the reconstructions of annual drought in this region, we suggest collecting tree cores from the southern side of old trees growing at stressed sites.

Parametri branik dreves Pinus nigra (Arnold) in njihov klimatski signal

The first exploration of climate signal in tree-rings of Black pine (P. nigra Arnold), using minimum blue intensity method, is presented. Sampled trees were growing on site Kojnik (Slovenia). For resin extraction and scanning, 5 mm thick cores were prepared. Whole tree-ring widths were measured, as well as the width and density of early- and latewood. To remove age trend and influence of non-climatic factors, raw measurements were standardized using spline function. In density measurements, highly significant correlation values were calculated between May-June summed precipitation and earlywood density (r = 0.64, p<0.001), while maximum latewood density correlates the best with mean June-August temperature (r = 0.42, p<0.01). In width measurements, the highest correlation was calculated between tree-ring width and mean June-August temperature (r = -0.62, p<0.001).

Climate, history and neutrality as drivers of mammal beta diversity in Europe: insights from multiscale deconstruction

1. Environmental sorting, historical factors and neutral dynamics may all drive beta diversity (change in species composition across space), but their relative importance remains unresolved. In the case of European mammals, key potential drivers of large-scale beta diversity include current climate, neutral dynamics and two historical factors: Pleistocene glaciations and peninsular dynamics (immigration from extra-regional eastern faunal source areas and inter-linked relictual survival and evolutionary differentiation in isolated areas). 2. We assessed the relative importance of these drivers using a novel analytical framework to deconstruct beta diversity of non-volant mammals in Europe (138 species) into its turnover (change in species composition because of species replacements) and nestedness components (change in species composition because of species richness differences) at continental and regional (250,000 km(2) ) scales. 3. We found continental-scale mammal beta diversity to be mainly caused by spatial turnover (99·9%), with only a small contribution (0·1%) from nestedness. 4. Current climate emerged as an important driver of beta diversity, given the strong continental-scale turnover, particularly in north-south direction, i.e., in line with the latitudinal climate gradient, and, more directly, the strong correlation of climate with spatial turnover at both continental and regional scales. 5. However, there was also evidence for the importance of non-climatic drivers. Notably, the compositional variation purely accounted for by space was greater than that purely accounted for by environment for both the turnover and the nestedness component of beta diversity. Furthermore, the strong longitudinal turnover within Southern Europe is in accordance with the region's long-term climatic stability having allowed multiple refugia and local evolutionary diversification. As expected from peninsular dynamics, there was increasing dissimilarity with geographic distance in an east-west direction because of nestedness, but only in Central and Northern Europe. 6. In conclusion, European mammal beta diversity mainly reflects spatial turnover and only to a limited extent nestedness and is driven by current climate in combination with historical - and perhaps, neutral - dynamics. These findings suggest that a key challenge for climate-change predictive studies will be taking the influence of non-climatic factors into account.

The dynamics of climate elements and land drainage impact on hydrologic conditions in a lakeland blind drainage area

Abstract: The assessment of climate dynamics and the impact of land drainage systems on lakeland blind drainage area was the problem studied in the paper. The research area was located based on relative stability of non-climatic physiographic characteristics and water management practices over a longer time-scale. Thus, the influence of non-climatic factors on water storage could be omitted. The study site was situated in Warmia region in the Doplyw spod Nowej Wsi catchment (27.53 km). One of local seepage ponds called Bagna Ramuckie within the aforementioned catchment was investigated. The study covered the time period since the first half of the 19 century to the year 2005. The decisive factors affecting processes of increase and decrease of pond water surface area in considered spatial units were the trends of air temperature over the long time scale. It was indicated that natural enlargement of water surface area in the pond occurred after 40-years long period of air temperature decrease and the decline followed 20-year-long period of air temperature rise. Precipitation did not show any trends for long periods but typical cyclic changes of precipitation over a short time-scale. These pluvial cycles stimulated or destimulated processes of water surface changes additionally over short periods. The first episode of water surface decrease in the seepage pond occurred when air temperature rise trend coincided with intensive land drainage and changes in some land management patterns (the 2 half of the 19 century). Nevertheless, during the 20 century water management practices were rather stable and did not have any impact on rise or decline of seepage pond water surface area.

Estimating Recharge Rates with Analytic Element Models and Parameter Estimation

Quantifying the spatial and temporal distribution of recharge is usually a prerequisite for effective ground water flow modeling. In this study, an analytic element (AE) code (GFLOW) was used with a nonlinear parameter estimation code (UCODE) to quantify the spatial and temporal distribution of recharge using measured base flows as calibration targets. The ease and flexibility of AE model construction and evaluation make this approach well suited for recharge estimation. An AE flow model of an undeveloped watershed in northern Wisconsin was optimized to match median annual base flows at four stream gages for 1996 to 2000 to demonstrate the approach. Initial optimizations that assumed a constant distributed recharge rate provided good matches (within 5%) to most of the annual base flow estimates, but discrepancies of >12% at certain gages suggested that a single value of recharge for the entire watershed is inappropriate. Subsequent optimizations that allowed for spatially distributed recharge zones based on the distribution of vegetation types improved the fit and confirmed that vegetation can influence spatial recharge variability in this watershed. Temporally, the annual recharge values varied >2.5-fold between 1996 and 2000 during which there was an observed 1.7-fold difference in annual precipitation, underscoring the influence of nonclimatic factors on interannual recharge variability for regional flow modeling. The final recharge values compared favorably with more labor-intensive field measurements of recharge and results from studies, supporting the utility of using linked AE-parameter estimation codes for recharge estimation.