scholarly journals Long-term patterns in dissolved organic carbon in boreal lakes: the role of incident radiation, precipitation, air temperature, southern oscillation and acid deposition

2003 ◽  
Vol 7 (3) ◽  
pp. 390-398 ◽  
Author(s):  
J. J. Hudson ◽  
P. J. Dillon ◽  
K. M. Somers
Keyword(s):  
Organic Carbon ◽  
Solar Radiation ◽  
Regression Model ◽  
Air Temperature ◽  
Southern Oscillation ◽  
Summer Precipitation ◽  
Winter Precipitation ◽  
Boreal Lakes ◽  
Doc Concentration

Abstract. Both lake-specific (e.g. pH) and regional (e.g. precipitation) factors affect DOC concentration and pattern. Using annual DOC concentration in nine boreal lakes in the ice-free season, the potential influences of five regional factors, air temperature, precipitation, SO4 deposition, solar radiation (photosynthetically active radiation, or PAR) and the southern oscillation index (SOI) have been explored through multiple regression. Mean solar radiation, winter precipitation and summer precipitation explained 59% of the variation in the mean DOC concentration (F3,17= 8.29, p= 0.0013). Solar radiation and winter precipitation were correlated, negatively, while summer precipitation was correlated, positively, with DOC concentration. Because these relationships were based on only 21 years of data (1978 to 1998), the significance of the parameters in the regression model was evaluated with a randomisation test. This re-analysis indicated that summer precipitation did not contribute significantly to the regression model ( prand= 0.183). The final multiple regression explained 50% of the variation in DOC (F2,18 = 9.33, prand= 0.002) based on solar radiation and winter precipitation. These results suggest that solar radiation and winter precipitation have a significant role in determining long-term DOC concentration in boreal lakes. Keywords: dissolved-organic-carbon, lakes, climate, solar-radiation, precipitation, acid-precipitation, Precambrian-Shield-Ontario

scholarly journals High correlation between winter precipitation and air temperature in heavy-snowfall areas in Japan

2008 ◽  
Vol 49 ◽  
pp. 7-10 ◽  
Author(s):  
Yukari Takeuchi ◽  
Yasoichi Endo ◽  
Shigeki Murakami
Keyword(s):  
Air Temperature ◽  
Winter Precipitation ◽  
The Sea Of Japan ◽  
Heavy Snowfall ◽  
Temperature And Precipitation ◽  
Effective Factor ◽  
Precipitation Decrease ◽  
Precipitation Ratio ◽  
Term Data

AbstractLong-term data of winter air temperature and precipitation were analyzed and the correlation between them investigated in order to identify the factors influencing snow reduction during the recent warmer winters in the heavy-snowfall areas in Japan. A high negative correlation between winter precipitation and air temperature was identified in the heavy-snowfall areas on the Sea of Japan side in the center of the main island (Honshu). It was confirmed that precipitation is mainly caused by cold winter monsoons, and thus correlates to a large extent with air temperature in these areas. The precipitation decrease can be considered an effective factor for the recent reduction in snow as well as the snowfall to precipitation ratio. This should be taken into account for a better prediction of snow reduction in relation to global warming.

scholarly journals Spatial Analysis of Seasonal Precipitation Using Various Interpolation Methods in the Euphrates Basin, Turkey

2021 ◽  
Author(s):  
Okan Mert Katipoğlu
Keyword(s):  
Spatial Distribution ◽  
Geographical Information Systems ◽  
Polynomial Interpolation ◽  
Estimation Method ◽  
Summer Precipitation ◽  
Winter Precipitation ◽  
Geographical Information ◽  
Seasonal Precipitation ◽  
Interpolation Methods

Abstract It is vital to accurately map the spatial distribution of precipitation, which is widely used in many fields such as hydrology, climatology, meteorology, ecology, and agriculture. In this study, it was aimed to reveal the spatial distribution of seasonal long-term average precipitation in the Euphrates Basin by using various interpolation methods. For this reason, Simple Kriging (SK), Ordinary Kriging (OK), Universal Kriging (UK), Ordinary CoKriging (OCK), Empirical Bayesian Kriging (EBK), Radial Basis Functions (Completely Regularized Spline (CRS), Thin Plate Spline (TPS), Multiquadratic, Inverse Multiquadratic (IM), Spline with Tensor (ST)), Local Polynomial Interpolation (LPI), Global Polynomial Interpolation (GPI), Inverse Distance Weighting (IDW) methods have been applied in the Geographical Information Systems (GIS) environment. Long-term seasonal precipitation averages between 1966 and 2017 are presented as input for the prediction of precipitation maps. The accuracy of the precipitation prediction maps created was based on root mean square error (RMSE) values obtained from the cross-validation tests. The method of precipitation by interpolation yielding the lowest RMSE was selected as the most appropriate method. As a result of the study, OCK in spring and winter precipitation, LPI in summer precipitation, and OK in autumn precipitation were determined as the most appropriate estimation method.

scholarly journals Dissolved organic carbon dynamics in a UK podzolic moorland catchment: linking storm hydrochemistry, flow path analysis and sorption experiments

2012 ◽  
Vol 9 (1) ◽  
pp. 209-251 ◽  
Author(s):  
M. I. Stutter ◽  
S. M. Dunn ◽  
D. G. Lumsdon
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Soil Conditions ◽  
Dry Period ◽  
Flow Paths ◽  
Selective Filtration ◽  
Antecedent Conditions ◽  
Doc Concentration ◽  
Mineral Soils

Abstract. Better knowledge of spatial and temporal delivery of dissolved organic Carbon (DOC) in small catchments is required to understand the mechanisms behind reported long-term changes in C fluxes from some peatlands. We monitored two storms with contrasting seasons and antecedent conditions in a small upland UK moorland catchment. We examined DOC concentrations and specific UV absorbance (SUVA at 285 nm), together with solute concentrations required to undertake end member mixing analyses to define dominant flow paths contributing to streamflow. This was combined with laboratory soil-solution equilibrations. We aimed to resolve how seasonal biogeochemical processing of DOC and flowpath changes in organo-mineral soils combine to affect DOC exported via the stream. An August storm following a dry period gave maximum DOC concentration of 10 mg l−1. Small DOC:DON ratios (16–28) and SUVA (2.7–3.6 l mg−1 m−1) was attributed to filtration of aromatic compounds associated with up to 53% B horizon flow contributions. This selective filtration of high SUVA DOC was reproduced in the experimental batch equilibration system. For a November storm, wetter antecedent soil conditions led to enhanced soil connectivity with the stream and seven times greater DOC stream-load (maximum concentration 16 mg l−1). This storm had a 63% O horizon flow contribution at its peak, limited B horizon buffering and consequently more aromatic DOC (SUVA 3.9–4.5 l mg−1 m−1 and DOC:DON ratio 35–43). We suggest that simple mixing of waters from different flow paths cannot alone explain the differences in DOC compositions between August and November and biogeochemical processing of DOC is required to fully explain the observed stream DOC dynamics. This is in contrast to other studies proposing hydrological controls and provides evidence that DOC biogeochemistry must be incorporated in modelling to predict the impacts of changes in DOC delivery to aquatic systems.

Long-term changes in surface solar radiation and their effects on air temperature in the Shanghai region

2014 ◽  
Vol 35 (12) ◽  
pp. 3385-3396 ◽  
Author(s):  
Jianming Deng ◽  
Yunlin Zhang ◽  
Boqiang Qin ◽  
Kun Shi
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Surface Solar Radiation ◽  
Long Term Changes

Linking organic carbon sedimentation, burial efficiency, and long-term accumulation in boreal lakes

2014 ◽  
Vol 119 (5) ◽  
pp. 836-847 ◽  
Author(s):  
Marie-Eve Ferland ◽  
Yves T. Prairie ◽  
Cristian Teodoru ◽  
Paul A. del Giorgio
Keyword(s):  
Organic Carbon ◽  
Boreal Lakes ◽  
Burial Efficiency

scholarly journals Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 455 ◽  
Author(s):  
Boksoon Myoung ◽  
Sang-Wook Yeh ◽  
Jinwon Kim ◽  
Menas Kafatos
Keyword(s):  
Regression Model ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Winter Precipitation ◽  
Precipitation Variability ◽  
Tropical Pacific ◽  
Mirror Image ◽  
Western Tropical Pacific

One of the primary meteorological causes of the winter precipitation deficits and droughts in California (CA) is anomalous developments and maintenance of upper-tropospheric ridges over the northeastern Pacific. In order to understand and find the key factors controlling the winter precipitation variability in CA, the present study examines two dominant atmospheric modes of the 500 hPa geopotential height in the Northern Hemisphere using an Empirical Orthogonal Function (EOF) and their associated large-scale circulation patterns for the last 41 winters (1974/75–2014/15). Explaining 17.5% of variability, the second mode (EOF2) shows strong anti-cyclonic circulations in the North Pacific and cyclonic circulations in the eastern USA and mid-latitude North Atlantic, similar to the atmospheric circulation observed in the 2013/14 drought of CA. EOF2 is tightly and significantly correlated with CA winter precipitation. EOF2 is associated with warm western‒cool eastern tropical Pacific, resembling a mirror image of canonical El Niño events. In particular, it is found that, since the mid-1990s, sea surface temperatures (SSTs) in the western tropical Pacific have been more tightly correlated with EOF2 and with the variability of CA precipitation. A diagnostic regression model based on the west‒east SST difference in the tropical Pacific developed for two recent decades (1994/95–2014/15) has been found to capture the slow-moving interannual variability of the CA winter precipitation (about 50%). The regression model performs well, especially for the central and northern CA precipitation, where the impacts of El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on precipitation are indecisive. Our results emphasize the significant role of the western tropical Pacific SST forcing in the recent past, and in turn on CA droughts and potentially other precipitation extremes.

scholarly journals Dissolved organic carbon dynamics in a UK podzolic moorland catchment: linking storm hydrochemistry, flow path analysis and sorption experiments

2012 ◽  
Vol 9 (6) ◽  
pp. 2159-2175 ◽  
Author(s):  
M. I. Stutter ◽  
S. M. Dunn ◽  
D. G. Lumsdon
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Preliminary Evidence ◽  
Soil Conditions ◽  
Dry Period ◽  
Flow Paths ◽  
Antecedent Conditions ◽  
Doc Concentration ◽  
Mineral Soils

Abstract. Better knowledge of spatial and temporal delivery of dissolved organic carbon (DOC) in small catchments is required to understand the mechanisms behind reported long-term changes in C fluxes from some peatlands. We monitored two storms with contrasting seasons and antecedent conditions in a small upland UK moorland catchment. We examined DOC concentrations and specific UV absorbance (SUVA at 285 nm), together with solute concentrations required to undertake end-member mixing analyses to define dominant flow paths contributing to streamflow. This was combined with laboratory soil-solution equilibrations. We aimed to resolve how seasonal biogeochemical processing of DOC and flowpath changes in organo-mineral soils combine to affect DOC exported via the stream. An August storm following a dry period gave maximum DOC concentration of 10 mg l−1. Small DOC:DON ratios (16–28) and SUVA (2.7–3.6 l mg−1 m−1) was attributed to filtration of aromatic compounds associated with up to 53% B horizon flow contributions. This selective filtration of high SUVA DOC was reproduced in the experimental batch equilibration system. For a November storm, wetter antecedent soil conditions led to enhanced soil connectivity with the stream and seven times greater DOC stream-load (maximum concentration 16 mg l−1). This storm had a 63% O horizon flow contribution at its peak, limited B horizon buffering and consequently more aromatic DOC (SUVA 3.9–4.5 l mg−1 m−1 and DOC:DON ratio 35–43). We suggest that simple mixing of waters from different flow paths cannot alone explain the differences in DOC compositions between August and November and biogeochemical processing of DOC is required to fully explain the observed stream DOC dynamics. This preliminary evidence is in contrast to other studies proposing hydrological controls on the nature of DOC delivered to streams. Although our study is based only on two storms of very different hydrological and biogeochemical periods, this should promote wider study of DOC biogeochemical alteration in headwaters so that this be better incorporated in modelling to predict the impacts of changes in DOC delivery to, and fate in, aquatic systems.

scholarly journals Seasonal-to-Interannual Prediction Skills of Near-Surface Air Temperature in the CMIP5 Decadal Hindcast Experiments

2016 ◽  
Vol 29 (4) ◽  
pp. 1511-1527 ◽  
Author(s):  
Jung Choi ◽  
Seok-Woo Son ◽  
Yoo-Geun Ham ◽  
June-Yi Lee ◽  
Hye-Mi Kim
Keyword(s):  
Air Temperature ◽  
Climate Models ◽  
Southern Oscillation ◽  
Surface Air Temperature ◽  
Equatorial Pacific ◽  
Prediction Skill ◽  
Good Opportunity ◽  
Near Surface ◽  
Global Mean

Abstract This study explores the seasonal-to-interannual near-surface air temperature (TAS) prediction skills of state-of-the-art climate models that were involved in phase 5 of the Coupled Model Intercomparison Project (CMIP5) decadal hindcast/forecast experiments. The experiments are initialized in either November or January of each year and integrated for up to 10 years, providing a good opportunity for filling the gap between seasonal and decadal climate predictions. The long-lead multimodel ensemble (MME) prediction is evaluated for 1981–2007 in terms of the anomaly correlation coefficient (ACC) and mean-squared skill score (MSSS), which combines ACC and conditional bias, with respect to observations and reanalysis data, paying particular attention to the seasonal dependency of the global-mean and equatorial Pacific TAS predictions. The MME shows statistically significant ACCs and MSSSs for the annual global-mean TAS for up to two years, mainly because of long-term global warming trends. When the long-term trends are removed, the prediction skill is reduced. The prediction skills are generally lower in boreal winters than in other seasons regardless of lead times. This lack of winter prediction skill is attributed to the failure of capturing the long-term trend and interannual variability of TAS over high-latitude continents in the Northern Hemisphere. In contrast to global-mean TAS, regional TAS over the equatorial Pacific is predicted well in winter. This is mainly due to a successful prediction of the El Niño–Southern Oscillation (ENSO). In most models, the wintertime ENSO index is reasonably well predicted for at least one year in advance. The sensitivity of the prediction skill to the initialized month and method is also discussed.

scholarly journals Dissolved organic carbon concentrations vary with season and land use – investigations from two fens in Northeastern Germany over two years

2014 ◽  
Vol 11 (5) ◽  
pp. 7079-7111 ◽  
Author(s):  
M. Schwalm ◽  
J. Zeitz
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Environmental Concern ◽  
Doc Export ◽  
Doc Concentration ◽  
Agricultural Use ◽  
Northeastern Germany ◽  
Carbon Concentrations ◽  
Discharge Measurements

Abstract. The rising export of dissolved organic carbon (DOC) from peatlands during the last 20 years is of great environmental concern, as DOC harms drinking water quality and diminishes the carbon storage of peatlands. Lack of knowledge particularly exists for fens. The aim of our study was to determine DOC concentrations at an agriculturally used fen and a rewetted fen throughout the year. We measured DOC concentrations in ditch water of these fens in 2011 and 2012. Furthermore, discharge measurements were condcucted to detect DOC export. Overall DOC concentrations at our agriculturally used site and at our rewetted site were 35 mg L−1 and 26 mg L−1 (median), respectively. The maximum DOC concentration at our agriculturally used site was twice as high as at the rewetted site (134 mg L−1 vs. 61 mg L−1). Annual DOC export was calculated for the rewetted site, amounting to 200 kg C ha−1 on average. Our results suggest that rewetting of degraded fens reduces DOC export in the long-term, while agricultural use of fens leads to enhanced decomposition and thus, elevates DOC export.

scholarly journals Comparison of Air Temperature Characteristics in Forest Communities in Puszcza Borecka and in Open Space

2010 ◽  
Vol 14 (1) ◽  
pp. 135-143
Author(s):  
Katarzyna Pietras
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Open Space ◽  
Thermal Conditions ◽  
Forest Communities ◽  
Temperature Characteristics ◽  
Tree Crowns

Abstract Changes in similarities of five forest communities and of open space taking place during the year were analyzed in the scope of twelve daily and monthly characteristics of air temperature. The density of tree crowns having impact on the level of solar radiation reaching the ground during the day and the level of long term nocturnal emissions is the most important factor shaping thermal conditions in the forest.

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