scholarly journals Deep desiccation of soils observed by long-term high-resolution measurements on a large inclined lysimeter

2021 ◽  
Vol 25 (6) ◽  
pp. 3519-3538
Author(s):  
Markus Merk ◽  
Nadine Goeppert ◽  
Nico Goldscheider
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Vegetation Period ◽  
Test Site ◽  
Change Point Detection ◽  
Key Factors ◽  
Moisture Fluxes ◽  
Meteorological Influences ◽  
Point Detection

Abstract. Availability of long-term and high-resolution measurements of soil moisture is crucial when it comes to understanding all sorts of changes to past soil moisture variations and the prediction of future dynamics. This is particularly true in a world struggling against climate change and its impacts on ecology and the economy. Feedback mechanisms between soil moisture dynamics and meteorological influences are key factors when it comes to understanding the occurrence of drought events. We used long-term high-resolution measurements of soil moisture on a large inclined lysimeter at a test site near Karlsruhe, Germany. The measurements indicate (i) a seasonal evaporation depth of over 2 m. Statistical analysis and linear regressions indicate (ii) a significant decrease in soil moisture levels over the past 2 decades. This decrease is most pronounced at the start and the end of the vegetation period. Furthermore, Bayesian change-point detection revealed (iii) that this decrease is not uniformly distributed over the complete observation period. The largest changes occur at tipping points during years of extreme drought, with significant changes to the subsequent soil moisture levels. This change affects not only the overall trend in soil moisture, but also the seasonal dynamics. A comparison to modeled data showed (iv) that the occurrence of deep desiccation is not merely dependent on the properties of the soil but is spatially heterogeneous. The study highlights the importance of soil moisture measurements for the understanding of moisture fluxes in the vadose zone.

scholarly journals Deep desiccation of soils observed by long-term high-resolution measurements on a large inclined lysimeter

2020 ◽  
Author(s):  
Markus Merk ◽  
Nadine Goeppert ◽  
Nico Goldscheider
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Vegetation Period ◽  
Test Site ◽  
Change Point Detection ◽  
Key Factors ◽  
Moisture Fluxes ◽  
Meteorological Influences ◽  
Point Detection

Abstract. Availability of long-term and high-resolution measurements of soil moisture is crucial when it comes to understanding all sorts of changes to past soil moisture variations and the prediction of future dynamics. This is particularly true in a world struggling against climate change and its impacts on ecology and economy. Feedback mechanisms between soil moisture dynamics and meteorological influences are key factors when it comes to understanding the occurrence of drought events. We used long-term high-resolution measurements of soil moisture on a large inclined lysimeter at a test site near Karlsruhe, Germany. The measurements indicate (i) a seasonal evaporation depth of over two meters. Statistical analysis and linear regressions indicate (ii) a significant decrease in soil moisture levels over the past two decades. This decrease is most pronounced at the start and the end of the vegetation period. Furthermore, Bayesian change point detection revealed (iii), that this decrease is not uniformly distributed over the complete observation period. Largest changes occur at tipping points during years of extreme drought, with significant changes to the subsequent soil moisture levels. This change affects not only the overall trend in soil moisture, but also the seasonal dynamics. A comparison to modeled data showed (iv) that the occurrence of deep desiccation is not merely dependent on the properties of the soil but is spatially heterogeneous. The study highlights the importance of soil moisture measurements for the understanding of soil moisture fluxes in the vadose zone.

scholarly journals High-resolution drought simulations and comparison to soil moisture observations in Germany

2021 ◽  
Author(s):  
Friedrich Boeing ◽  
Oldrich Rakovech ◽  
Rohini Kumar ◽  
Luis Samaniego ◽  
Martin Schrön ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Information Systems ◽  
High Resolution ◽  
Water Cycle ◽  
Cosmic Ray ◽  
Vegetation Period ◽  
Moisture Index ◽  
Distributed Sensor ◽  
Local Risk ◽  
The One

Abstract. The 2018–2020 consecutive drought events in Germany resulted in impacts related with several sectors such as agriculture, forestry, water management, industry, energy production and transport. A major national operational drought information system is the German Drought Monitor (GDM), launched in 2014. It provides daily soil moisture (SM) simulated with the mesoscale hydrological model (mHM) and its related soil moisture index at a spatial resolution of 4 × 4 km2. Key to preparedness for extreme drought events are high-resolution information systems. The release of the new soil map BUEK200 allowed to increase the model resolution to ~1.2 × 1.2 km2, which is used in the second version of the GDM. In this paper, we explore the ability to provide drought information on the one-kilometer scale in Germany. Therefore, we compare simulated SM dynamics using homogenized and deseasonalized SM observations to evaluate the high-resolution drought simulations of the GDM. These SM observations are obtained from single profile measurements, spatially distributed sensor networks, cosmic-ray neutron stations and lysimeters at 40 sites in Germany. The results show that the agreement of simulated and observed SM dynamics is especially high in the vegetation period (0.84 median correlation R) and lower in winter (0.59 median R). Lower agreement in winter results from methodological uncertainties in simulations as well as in observations. Moderate but significant improvements between the first and second GDM version to observed SM were found in correlations for autumn (+0.07 median R) and winter (+0.12 median R). The annual drought intensity ranking and the spatial structure of drought events over the past 69 years is comparable for the two GDM versions. However, the higher resolution of the second GDM version allows a much more detailed representation of the spatial variability of SM, which is particularly beneficial for local risk assessments. Furthermore, the results underline that nationwide drought information systems depend both on appropriate simulations of the water cycle and a broad, high-quality observational soil moisture database.

scholarly journals A Remote Sensing-Based Assessment of Water Resources in the Arabian Peninsula

2021 ◽  
Vol 13 (2) ◽  
pp. 247
Author(s):  
Youssef Wehbe ◽  
Marouane Temimi
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Water Resources ◽  
Change Point ◽  
Arabian Peninsula ◽  
Change Point Detection ◽  
Change Points ◽  
Point Detection ◽  
Precipitation Trends

A better understanding of the spatiotemporal distribution of water resources is crucial for the sustainable development of hyper-arid regions. Here, we focus on the Arabian Peninsula (AP) and use remotely sensed data to (i) analyze the local climatology of total water storage (TWS), precipitation, and soil moisture; (ii) characterize their temporal variability and spatial distribution; and (iii) infer recent trends and change points within their time series. Remote sensing data for TWS, precipitation, and soil moisture are obtained from the Gravity Recovery and Climate Experiment (GRACE), the Tropical Rainfall Measuring Mission (TRMM), and the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), respectively. The study relies on trend analysis, the modified Mann–Kendall test, and change point detection statistics. We first derive 10-year (2002–2011) seasonal averages from each of the datasets and intercompare their spatial organization. In the absence of large-scale in situ data, we then compare trends from GRACE TWS retrievals to in situ groundwater observations locally over the subdomain of the United Arab Emirates (UAE). TWS anomalies vary between −6.2 to 3.2 cm/month and −6.8 to −0.3 cm/month during the winter and summer periods, respectively. Trend analysis shows decreasing precipitation trends (−2.3 × 10−4 mm/day) spatially aligned with decreasing soil moisture trends (−1.5 × 10−4 g/cm3/month) over the southern part of the AP, whereas the highest decreasing TWS trends (−8.6 × 10−2 cm/month) are recorded over areas of excessive groundwater extraction in the northern AP. Interestingly, change point detection reveals increasing precipitation trends pre- and post-change point breaks over the entire AP region. Significant spatial dependencies are observed between TRMM and GRACE change points, particularly over Yemen during 2010, revealing the dominant impact of climatic changes on TWS depletion.

scholarly journals THE EFFECT OF PRECIPITATIONS IN A VEGETATION PERIOD ON PRODUCTIVITY OF THE ZONED SPRING BARLEY VARIETIES IN THE ARID CENTRAL ZONE OF THE REPUBLIC OF KALMYKIA

2019 ◽  
pp. 14-17 ◽  
Author(s):  
B. А. Goldvarg ◽  
М. V. Boktaev ◽  
Е. G. Filippov ◽  
А. А. Dontsova
Keyword(s):  
Soil Moisture ◽  
Spring Barley ◽  
Central Zone ◽  
Grain Filling ◽  
Vegetation Period ◽  
Field Trials ◽  
Limiting Factors ◽  
The Republic ◽  
Variety Testing

In the arid central zone of the Republic of Kalmykia, one of the limiting factors that affects spring barley productivity is the soil moisture content during a vegetation period. The paper discusses the results of a long-term research of zoned spring barley varieties of various breeding institutions in the experimental field of the KRIA named after M. B. Narmaeva, a branch of the FSBSI “PAFRC RAS” to study the effect of instability of soil moisture in a vegetation period on their productivity and especially in the period of grain filling. Field trials were carried out according to the Methods of State Variety Testing of agricultural crops and Methodology of a field trial. In the course of the studies it was found that in arid years the variety “Shchedry” formed a larger yield than that of other zoned varieties. Moreover, in the wet years of 2016 and 2017 the variety “Shchedry” productivity was inferior to the varieties “Prerii” and “Strannik” on average. It has been revealed that in conditions with uneven precipitation in different years, June precipitation has a decisive effect on spring barley productivity in the central zone of the Republic of Kalmykia.

The 2018 drought and its consequences: Investigating the resilience of different tree species based on comprehensive long-term monitoring of forest hydrology

2020 ◽  
Author(s):  
Theresa Blume ◽  
Daniel Balanzategui ◽  
Lisa Schneider ◽  
Daniel Rasche ◽  
Markus Morgner ◽  
...  
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Water Deficit ◽  
Tree Growth ◽  
Tree Species ◽  
Temperate Forest ◽  
Subsurface Water ◽  
Forest Stands ◽  
Northeastern Germany

<p>Many forests in Central Europe experienced unprecedented drought conditions in 2018. The exceptionally long dry period, lasting from early-summer 2018 and into the winter, was followed by another dry summer with record-breaking temperatures.   Ecohydrological consequences of extended droughts for these temperate forest systems are difficult to anticipate, and investigating the resilience of forest hydrological systems requires comprehensive and systematic long-term observations.</p><p>Monitoring at the TERENO-NE temperate forest observatory in northeastern Germany includes input characterization (throughfall and stemflow), high-resolution soil moisture observations in 14 different forest stands down to a depth of 2 m below the soil surface, shallow and deep groundwater observations, sap flow, tree water deficit and high-resolution tree growth measurements since 2012. The investigated forest stands cover the three tree species pine, oak and beech in both pure and mixed stands. This is complemented by terrestrial gravimetric measurements of total water storage changes. Steep hillslope transects allow us to investigate the impact of presence or absence of groundwater availability on tree water uptake and growth.</p><p>We find that after the unprecedented drought in 2018, which already had pronounced ecohydrological effects, the rainfall amounts over the winter 2018/19 were insufficient to refill the subsurface water storages. Dry conditions altered the growth phenology of each monitored tree species, while tree-water deficit and tree growth were negatively impacted in both years, but to varying extent. Soil moisture storage and dynamics are strongly affected and the drought caused a long-term memory effect.</p>

scholarly journals Long-Term and High-Resolution Global Time Series of Brightness Temperature from Copula-Based Fusion of SMAP Enhanced and SMOS Data

2018 ◽  
Vol 10 (11) ◽  
pp. 1842 ◽  
Author(s):  
Christof Lorenz ◽  
Carsten Montzka ◽  
Thomas Jagdhuber ◽  
Patrick Laux ◽  
Harald Kunstmann
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
High Resolution ◽  
Brightness Temperature ◽  
Spatial Resolution ◽  
Prediction Models ◽  
Weather Prediction ◽  
Brightness Temperatures ◽  
Climate Analysis

Long and consistent soil moisture time series at adequate spatial resolution are key to foster the application of soil moisture observations and remotely-sensed products in climate and numerical weather prediction models. The two L-band soil moisture satellite missions SMAP (Soil Moisture Active Passive) and SMOS (Soil Moisture and Ocean Salinity) are able to provide soil moisture estimates on global scales and in kilometer accuracy. However, the SMOS data record has an appropriate length of 7.5 years since late 2009, but with a coarse resolution of ∼25 km only. In contrast, a spatially-enhanced SMAP product is available at a higher resolution of 9 km, but for a shorter time period (since March 2015 only). Being the fundamental observable from passive microwave sensors, reliable brightness temperatures (Tbs) are a mandatory precondition for satellite-based soil moisture products. We therefore develop, evaluate and apply a copula-based data fusion approach for combining SMAP Enhanced (SMAP_E) and SMOS brightness Temperature (Tb) data. The approach exploits both linear and non-linear dependencies between the two satellite-based Tb products and allows one to generate conditional SMAP_E-like random samples during the pre-SMAP period. Our resulting global Copula-combined SMOS-SMAP_E (CoSMOP) Tbs are statistically consistent with SMAP_E brightness temperatures, have a spatial resolution of 9 km and cover the period from 2010 to 2018. A comparison with Service Soil Climate Analysis Network (SCAN)-sites over the Contiguous United States (CONUS) domain shows that the approach successfully reduces the average RMSE of the original SMOS data by 15%. At certain locations, improvements of 40% and more can be observed. Moreover, the median NSE can be enhanced from zero to almost 0.5. Hence, CoSMOP, which will be made freely available to the public, provides a first step towards a global, long-term, high-resolution and multi-sensor brightness temperature product, and thereby, also soil moisture.

scholarly journals Modeling the first wave of Covid-19 pandemic in the Republic of Cyprus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergios Agapiou ◽  
Andreas Anastasiou ◽  
Anastassia Baxevani ◽  
Christos Nicolaides ◽  
Georgios Hadjigeorgiou ◽  
...  
Keyword(s):  
Change Point Detection ◽  
Short Term ◽  
Intervention Measures ◽  
The Republic ◽  
The Government ◽  
Republic Of Cyprus ◽  
Government Change ◽  
Point Detection ◽  
Data Analytic

AbstractWe present different data analytic methodologies that have been applied in order to understand the evolution of the first wave of the Coronavirus disease 2019 in the Republic of Cyprus and the effect of different intervention measures that have been taken by the government. Change point detection has been used in order to estimate the number and locations of changes in the behaviour of the collected data. Count time series methods have been employed to provide short term projections and a number of various compartmental models have been fitted to the data providing with long term projections on the pandemic’s evolution and allowing for the estimation of the effective reproduction number.

A high-resolution, continuous δ13C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

2016 ◽  
Vol 53 (8) ◽  
pp. 795-801 ◽  
Author(s):  
Alain Mauviel ◽  
André Desrochers
Keyword(s):  
High Resolution ◽  
Key Factors ◽  
Eastern Canada ◽  
Initial Water ◽  
Variable Sampling ◽  
Data Points ◽  
Sampling Intervals ◽  
Baseline Values ◽  
Anticosti Island

One of the best-exposed and most complete stratigraphic records from paleotropical areas spanning the Ordovician–Silurian (O–S) boundary is located on Anticosti Island, eastern Canada. Our study is the first one to sample strata superbly exposed at low tide along the west coast of Anticosti Island, thus providing a previously unexploited, nearly complete stratigraphic interval (∼300 m) at the O–S boundary for δ13C chemostratigraphy. A new high-resolution δ13C curve with more than 500 data points spaced at every ∼0.5 m has been produced, rectifying important pitfalls of previously published δ13C curves (i.e., low sampling resolution, variable sampling intervals, stratigraphic gaps). This new high-resolution δ13C curve displays a lower and an upper positive Hirnantian Isotope Carbon Excursion (HICE) recognized elsewhere around the globe. The ascending limb of the lower HICE starting from baseline values of +0.5‰ corresponds to the upper 20 m of the late Katian Vauréal Formation, but δ13C peak values of +2.5‰ occur in the lower part of the Hirnantian Ellis Bay Formation. In spite of a δ13C record segmented by a few stratigraphic hiatuses, the upper HICE, with its peak values of +4.5‰, is well recorded in the upper part of the Hirnantian Ellis Bay Formation. When compared with sections from around the globe, our δ13C curve displays a distinct long-term trend with a long sustained lower HICE followed abruptly by the upper HICE and return to baseline values of +0.5‰ prior to the Rhuddanian. The continued descending isotopic trend well into the Becscie Formation suggests that the O–S boundary may occur at a higher stratigraphic level (up to 30 m) than previously interpreted. Active subsidence combined with moderate initial water depths prior to the Hirnantian were key factors controlling the deposition of a thick O–S sedimentary succession with a few hiatuses on Anticosti Island and capturing a comprehensive, reliable δ13C record across this interval.

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