A mass and energy balance‐based glacier melt module was coupled with the spatially distributed hydrological soil vegetation model and used to simulate the basin‐scale water and energy balance in the ...Zhadang glacier basin. Observed hourly meteorological data from 2011 to 2014 were used as model forcing data. The basin‐scale simulations were evaluated at both the point and areal scales using albedo, temperature, and height change on the glacier surface, as well as the mass balance and streamflow of the whole basin. The analysis showed that the model could effectively reproduce the key elements of the energy and mass balance of the Zhadang basin. The analysis demonstrates that radiation was the most important energy component accounting for 80% of total surface energy. On average, glacier runoff contributed to 64% of the total basin discharge during the study period. The overall streamflow was controlled by the glacier mass balance in 2012 and 2014, while temperature and precipitation affected hydrological processes the most during 2011 and 2013. Both high temperature and precipitation resulted in high total basin streamflow but via different mechanisms. High temperatures increase glacier mass loss and glacier melt runoff, whereas high precipitation decreases glacier melt runoff but produces high runoff in nonglacier areas. The early onset of the Indian monsoon with high snowfall reduces glacier surface melt but sustains basin discharge, positively affecting for water resources.
Key Points
Spatially distributed hydrological model DHSVM
The glacier runoff contributed 64.3% of the basin total discharge
Early onset of Indian monsoon is a positive effect for water resource
Gait and balance impairment is associated with poorer functional recovery after stroke. The cerebellum is known to be strongly implicated in the functional reorganization of motor networks in ...patients with stroke, especially for gait and balance functions.
To determine whether cerebellar intermittent θ-burst stimulation (CRB-iTBS) can improve balance and gait functions in patients with hemiparesis due to stroke.
This randomized, double-blind, sham-controlled phase IIa trial investigated efficacy and safety of a 3-week treatment of CRB-iTBS coupled with physiotherapy in promoting gait and balance recovery in patients with stroke. Thirty-six patients with consecutive ischemic chronic stroke in the territory of the contralateral middle cerebral artery with hemiparesis were recruited from a neuro-rehabilitation hospital. Participants were screened and enrolled from March 2013 to June 2017. Intention-to-treat analysis was performed.
Patients were randomly assigned to treatment with CRB-iTBS or sham iTBS applied over the cerebellar hemisphere ipsilateral to the affected body side immediately before physiotherapy daily during 3 weeks.
The primary outcome was the between-group difference in change from baseline in the Berg Balance Scale. Secondary exploratory measures included the between-group difference in change from baseline in Fugl-Meyer Assessment scale, Barthel Index, and locomotion assessment with gait analysis and cortical activity measured by transcranial magnetic stimulation in combination with electroencephalogram.
A total of 34 patients (mean SD age, 64 11.3 years; 13 women 38.2%) completed the study. Patients treated with CRB-iTBS, but not with sham iTBS, showed an improvement of gait and balance functions, as revealed by a pronounced increase in the mean (SE) Berg Balance Scale score (baseline: 34.5 3.4; 3 weeks after treatment: 43.4 2.6; 3 weeks after the end of treatment: 47.5 1.8; P < .001). No overall treatment-associated differences were noted in the Fugl-Meyer Assessment (mean SE, baseline: 163.8 6.8; 3 weeks after treatment: 171.1 7.2; 3 weeks after the end of treatment: 173.5 6.9; P > .05) and Barthel Index scores (mean SE, baseline: 71.1 4.92; 3 weeks after treatment: 88.8 2.1; 3 weeks after the end of treatment: 92.2 2.4; P > .05). Patients treated with CRB-iTBS, but not sham iTBS, showed a reduction of step width at the gait analysis (mean SE, baseline: 16.8 4.8 cm; 3 weeks after treatment: 14.3 6.2 cm; P < .05) and an increase of neural activity over the posterior parietal cortex.
Cerebellar intermittent θ-burst stimulation promotes gait and balance recovery in patients with stroke by acting on cerebello-cortical plasticity. These results are important to increase the level of independent walking and reduce the risk of falling.
ClinicalTrials.gov Identifier: NCT03456362.
► Mean energy balance closure at 173 FLUXNET sites is 0.84. ► Mean forest and non-forest closure does not differ. ► Significant differences in closure were found among plant functional types. ► ...Landscape-level vegetation variability should not be excluded from the interpretation.
The energy balance at most surface-atmosphere flux research sites remains unclosed. The mechanisms underlying the discrepancy between measured energy inputs and outputs across the global FLUXNET tower network are still under debate. Recent reviews have identified exchange processes and turbulent motions at large spatial and temporal scales in heterogeneous landscapes as the primary cause of the lack of energy balance closure at some intensively-researched sites, while unmeasured storage terms cannot be ruled out as a dominant contributor to the lack of energy balance closure at many other sites. We analyzed energy balance closure across 173 ecosystems in the FLUXNET database and explored the relationship between energy balance closure and landscape heterogeneity using MODIS products and GLOBEstat elevation data. Energy balance closure per research site (CEB,s) averaged 0.84±0.20, with best average closures in evergreen broadleaf forests and savannas (0.91–0.94) and worst average closures in crops, deciduous broadleaf forests, mixed forests and wetlands (0.70–0.78). Half-hourly or hourly energy balance closure on a percent basis increased with friction velocity (u*) and was highest on average under near-neutral atmospheric conditions. CEB,s was significantly related to mean precipitation, gross primary productivity and landscape-level enhanced vegetation index (EVI) from MODIS, and the variability in elevation, MODIS plant functional type, and MODIS EVI. A linear model including landscape-level variability in both EVI and elevation, mean precipitation, and an interaction term between EVI variability and precipitation had the lowest Akaike's information criterion value. CEB,s in landscapes with uniform plant functional type approached 0.9 and CEB,s in landscapes with uniform EVI approached 1. These results suggest that landscape-level heterogeneity in vegetation and topography cannot be ignored as a contributor to incomplete energy balance closure at the flux network level, although net radiation measurements, biological energy assimilation, unmeasured storage terms, and the importance of good practice including site selection when making flux measurements should not be discounted. Our results suggest that future research should focus on the quantitative mechanistic relationships between energy balance closure and landscape-scale heterogeneity, and the consequences of mesoscale circulations for surface-atmosphere exchange measurements.
On the basis of long time series of climate and discharge in 108 nonhumid catchments in China this study analyzes the spatial and temporal variability of annual water‐energy balance using the Budyko ...hypothesis. For both long‐term means and annual values of the water balances in the 108 catchments, Fu's formula derived from the Budyko hypothesis is confirmed. A high correlation and relatively small systematic error between the values of parameter ϖ in Fu's equation optimized from the water balance of individual year and calibrated from the long‐term mean water balance show that Fu's equation can be used for predicting the interannual variability of regional water balances. It has been found that besides the annual climate conditions the regional pattern of annual water‐energy balance is also closely correlated with the relative infiltration capacity (Ks/ir), relative soil water storage (Smax/E0), and the average slope (tan β). This enables one to estimate the parameter ϖ from catchment characteristics without calibration from the long time series of water balances. An empirical formula for the parameter ϖ in terms of the dimensionless landscape parameters is proposed. Applications of Fu's equation together with the parameter ϖ estimated by this empirical formula have shown that Fu's equation can predict both long‐term mean and annual value of actual evapotranspiration accurately and predict both long‐term mean and interannual variability of runoff reasonably. This implies that the Fu's equation can be used for predicting the annual water balance in ungauged basins.
Summer precipitation plays critical roles in the energy balance and the availability of fresh water over eastern China. However, little is known regarding the trend in local‐scale precipitation ...(LSP). Here we developed a novel method to determine LSP events in the summer afternoon throughout eastern China from 1970 to 2010 based on hourly gauge measurements. The LSP occurrence hours decrease at an annual rate of 0.25%, which varies considerably by region, ranging from 0.14% over the Yangtze River Delta to 0.56% over the Pearl River Delta. This declining frequency of LSP is generally accompanied by an increase in rain rate of LSP but a decrease in visibility, whose linkage to LSP events was investigated. In particular, more LSP events tended to form when the atmosphere was slightly polluted. Afterward, LSP was suppressed. These findings have important implications for improving our understanding of the climatology of daytime precipitation at local scales.
Plain Language Summary
Summer precipitation plays critical roles in the energy balance and the availability of fresh water over eastern China. However, the knowledge remains poorly understood regarding the trend of local‐scale precipitation (LSP). Long‐term hourly gauge data in the summer afternoon throughout eastern China for 1970 to 2010 reveal that LSP occurrence hours decrease at an annual rate of 0.25%, which differs greatly by region, ranging from 0.14% over the Yangtze River Delta to 0.56% over the Pearl River Delta. In contrast, large‐scale precipitation events do not show significant increasing/decreasing trends over most regions. Further, concurrent visibility observations exhibit a decreasing trend, whose linkage to declining LSP is investigated. In particular, more LSP events tend to form as the atmosphere is slightly polluted. Afterward, LSP is suppressed. The findings provide deep insight into how precipitation changes over long term from a perspective of smaller spatial scale rainfall.
Key Points
A novel method developed to identify a local‐scale precipitation event based on hourly rain gauge data
A widespread declining trend of daytime local‐scale precipitation events was observed in eastern China in summer for 1970 to 2010
Coincident increase in aerosol could partly account for the decreasing trend of local‐scale precipitation
Living systems break detailed balance at small scales, consuming energy and producing entropy in the environment to perform molecular and cellular functions. However, it remains unclear how broken ...detailed balance manifests at macroscopic scales and how such dynamics support higher-order biological functions. Here we present a framework to quantify broken detailed balance by measuring entropy production in macroscopic systems. We apply our method to the human brain, an organ whose immense metabolic consumption drives a diverse range of cognitive functions. Using whole-brain imaging data, we demonstrate that the brain nearly obeys detailed balance when at rest, but strongly breaks detailed balance when performing physically and cognitively demanding tasks. Using a dynamic Ising model, we show that these large-scale violations of detailed balance can emerge from fine-scale asymmetries in the interactions between elements, a known feature of neural systems. Together, these results suggest that violations of detailed balance are vital for cognition and provide a general tool for quantifying entropy production in macroscopic systems.
Accurately estimating basin‐wide snow water equivalent (SWE) is the most important unsolved problem in mountain hydrology. Models that rely on remotely sensed inputs are especially needed in ranges ...with few surface measurements. The NASA Airborne Snow Observatory (ASO) provides estimates of SWE at 50 m spatial resolution in several basins across the Western U.S. during the melt season. Primarily, water managers use this information to forecast snowmelt runoff into reservoirs; another impactful use of ASO measurements lies in validating and improving satellite‐based snow estimates or models that can scale to whole mountain ranges, even those without ground‐based measurements. We compare ASO measurements from 2013 to 2015 to four methods that estimate spatially distributed SWE: two versions of a SWE reconstruction method, spatial interpolation from snow pillows and courses, and NOAA's Snow Data Assimilation System (SNODAS). SWE reconstruction downscales energy forcings to compute potential melt, then multiplies those values by satellite‐derived estimates of fractional snow‐covered area to calculate snowmelt. The snowpack is then built in reverse from the date the snow is observed to disappear. The two SWE reconstruction models tested include one that employs an energy balance calculation of snowmelt, and one that combines net radiation and degree‐day approaches to estimate melt. Our full energy balance model, without ground observations, performed slightly better than spatial interpolation from snow pillows, having no systematic bias and 26% mean absolute error when compared to SWE from ASO. Both reconstruction models and interpolation were more accurate than SNODAS.
Key Points
Reconstructed snow water equivalent is verified with spatial snow measurements from the Airborne Snow Observatory
Reconstruction relies only on remotely sensed data and outperformed SNODAS and spatial interpolation from snow pillows
Two reconstruction models tested comprise a full energy balance model and a net radiation plus degree‐day model
Dynamic balance disorders are common impairments in People with Multiple Sclerosis (PwMS) leading to gait disorders and a higher risk of falling. However, the assessment of dynamic balance is still ...challenging and instrumented indexes provide objective and quantitative data of CoM movement and Base of Support, which are considered that are two key factors describing dynamic balance. This study aims at validating recent instrumented indexes based on the inverted pendulum model and characterizing dynamic balance disorders in PwMS. We clinically assessed 20 PwMS and we collected instrumented gait data through an optoelectronic system. Data from 20 Healthy Subjects (HS) were also considered as normative reference. Margin of Stability by HoF (MoS_Hof) and by Terry (MoS_Terry) at midstance, and Foot Placement Estimator (D
) at heel strike were calculated in mediolateral (ML) and anteroposterior (AP) directions, for both less affected and most affected sides for PwMS and for dominant and non-dominant side for HS. MoS_HOF well discriminated between PwMS and HS, followed by MoS_TERRY in ML direction (Mos_HOF: PwMS = 130.0 ± 27.2 mm, HS = 106.5 ± 18.6 mm,
< 0.001, MoS_TERRY: PwMS = 75.1 ± 24.3 mm, HS = 56.5 ± 23.4 mm,
< 0.02). MoS_HOF and MoS_TERRY discriminated between sides in both directions in PwMS. D
did not discriminate between groups and sides. Moderate correlations were found between all three indexes and clinical balance scales (from
= 0.02 to
= 0.66), energy recovery (from
= -0.77 to
= -0.11), single stance time (from
= -0.11 to
= 0.80) and step length (from
= -0.83 to
= -0.20). MoS_HOF resulted in the best index to describe dynamic balance disorders in PwMS: they keep CoM position far from the lateral and as close as possible to the anterior boundary of the Base of Support as preventive strategies to control balance perturbations. Furthermore, PwMS seem to use different preventive strategies in accordance with the specific lower limb impairments. This alters the physiological gait mechanisms increasing the energy expenditure and decreasing gait quality and dynamic balance.
By shifting winter precipitation into summer freshet, the cryosphere supports life across the world.
The sensitivity of this mechanism to climate and the role played by the cryosphere in the Earth's ...energy budget have motivated the development of a broad spectrum of predictive models. Such models represent seasonal snow and glaciers with various complexities and generally are not integrated with hydrologic models describing the fate of meltwater through the hydrologic budget. We present Snow Multidata Mapping and Modeling (S3M) v5.1, a spatially explicit and hydrology-oriented cryospheric model that simulates seasonal snow and glacier evolution through time and that can be natively coupled with distributed hydrologic models. Model physics include precipitation-phase partitioning, snow and glacier mass balances, snow rheology and hydraulics, a hybrid temperature-index and radiation-driven melt parametrization, and a data-assimilation protocol.
Comparatively novel aspects of S3M are an explicit representation of the spatial patterns of snow liquid-water content, the implementation of the Δh parametrization for distributed ice-thickness change, and the inclusion of a distributed debris-driven melt factor.
Focusing on its operational implementation in the northwestern Italian Alps, we show that S3M provides robust predictions of the snow and glacier mass balances at multiple scales, thus delivering the necessary information to support real-world hydrologic operations.
S3M is well suited for both operational flood forecasting and basic research, including future scenarios of the fate of the cryosphere and water supply in a warming climate.
The model is open source, and the paper comprises a user manual as well as resources to prepare input data and set up computational environments and libraries.
Remote sensing of evapotranspiration (ET) can help detect, map and provide guidance for crop water needs in irrigated lands. Two remote sensing ET models based on thermal infrared (TIR), the ...Two-Source Energy Balance (TSEB) and the Satellite-Based Energy Balance for Mapping Evapotranspiration with Internalized Calibration (METRIC), were tested for accuracy, and bias at fine (1m) and moderate (30–120m) spatial scales. Airborne and Landsat data were collected over Maricopa, Arizona in 2009 and 2011 as part of a cotton irrigation scheduling study. Based on soil moisture observations at 112 locations across 4.9ha and image data spanning two growing seasons, TSEB and METRIC were found similarly accurate at both fine and moderate scales with average discrepancies no more than 1.9mm/day. Tests at 1-m scales showed that TSEB and METRIC model sensitivities were seasonally correlated, with greater sensitivity modeled by METRIC in early growth and slightly greater sensitivity by TSEB at maturity. Time integration of flux estimates was done by assuming constant evaporative fraction and was also tested for 2011 data using ground-based TIR radiometers; this latter approach improved daily ET estimates by 0.8mm/day or better in two cases. Time-series assessment of the utility of using evaporative fraction as a water-stress indicator was tested using Landsat data and both TSEB and METRIC. Two early season water depletion events were detected and none in mid-season. The impact of overpass frequency upon ET estimates was tested for the field as a whole and found that cumulative ET estimates were significantly affected, up to 200mm out of ~1000mm consumed. Results from this study showed that for ET accuracy, TSEB and METRIC perform similarly. METRIC is preferred when model ancillary data are sparse, while TSEB is preferred when support data are plentiful. Future ET modeling should consider implementing both to take advantage of their seasonally dependent sensitivities.
•Thermal infrared-based ET remote sensing models, TSEB and METRIC both accurate to 1.9mm/day.•TSEB and METRIC model sensitivities seasonally correlated.•8-day satellite overpass frequency significantly improves ET estimates compared to 16-days.
PDF
