scholarly journals Impacts on Estuarine Ecosystem from Climate Changes Based on Modeling Experiments within Delaware Bay

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
High Resolution ◽  
Physical Environment ◽  
Climate Changes ◽  
River Flow ◽  
Salinity Gradient ◽  
Delaware Bay ◽  
Estuarine Ecosystem ◽  
Salt Intrusion ◽  
Shear Dispersion ◽  
Freshwater Resource

Coastal regions concentrate ecological behaviors, have more observations, permit high-resolution modeling, and serve as a good climate-changing sensor. For the Delaware Bay, a high-resolution hydro-dynamical model (ROMS) was tailored, validated and applied to hindcast its largely unrecorded physical environment, to investigate the roles of the physical environment influencing oyster diseases, and to inquire into the future fate of the bay in response to climate changes. Sensitivity studies suggested that 50-100-cm sea-level rise (SLR) in approximately 50-100 years may occur and salinize the Delaware Bay mainly through weakening salinity gradient and salt advection due to the intensified mixing induced by the widened bay. Highly correlating to mixing and therefore changing salt advection, the width of the bay mattered to salt intrusion distance more than the depth of the bay did. This conclusion is differenet than that from the classic theories that emphasize the depth in influencing the salt intrusion distance via the steady shear dispersion. The SLR-induced salinization may not be offset by intensified river flow input, but may be substantially mitigated by fixing the coastline (or width). Climate warming may warm the shallow and thermally sensitive bay. The warm and salty conditions would compromise freshwater resource in the upper bay and be generally unfavorable to oysters by promoting oyster diseases (i.e., MSX and Dermo). Salinization might occur in other similar estuaries of narrow geometry, shallow depth, and small volume.

Larval Behavior and Protective Implications for Sea Scallops and Surf Clams within the Middle Atlantic Bight: Part Two, Variability of Physical Environment and Larval Behaviors

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Physical Environment ◽  
Climate Changes ◽  
Larval Growth ◽  
Growth Patterns ◽  
Larval Behavior ◽  
Larval Release ◽  
Physical Conditions ◽  
Climatic Variations ◽  
Middle Atlantic ◽  
Sea Scallops

Larval growth and settlement rates are important larval behaviors for larval protections. The variability of larval growthsettlement rates and physical conditions for 2006-2012 and in the future with potential climate changes was studied using the coupling ROMS-IMBs, and new temperature and current indexes. Forty-four experimental cases were conducted for larval growth patterns and release mechanisms, showing the spatial, seasonal, annual, and climatic variations of larval growthsettlement rates and physical conditions, demonstrating that the slight different larval temperature-adaption and larval release strategies made difference in larval growth-settlement rates, and displaying that larval growth and settlement rates highly depended upon physical conditions and were vulnerable to climate changes.

scholarly journals d4PDF: large-ensemble and high-resolution climate simulations for global warming risk assessment

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Masayoshi Ishii ◽  
Nobuhito Mori
Keyword(s):  
Risk Assessment ◽  
Global Warming ◽  
High Resolution ◽  
Climate Changes ◽  
Future Climate ◽  
Atmospheric Models ◽  
Large Ensemble ◽  
Past Climate ◽  
The Past ◽  
Climate Simulations

Abstract A large-ensemble climate simulation database, which is known as the database for policy decision-making for future climate changes (d4PDF), was designed for climate change risk assessments. Since the completion of the first set of climate simulations in 2015, the database has been growing continuously. It contains the results of ensemble simulations conducted over a total of thousands years respectively for past and future climates using high-resolution global (60 km horizontal mesh) and regional (20 km mesh) atmospheric models. Several sets of future climate simulations are available, in which global mean surface air temperatures are forced to be higher by 4 K, 2 K, and 1.5 K relative to preindustrial levels. Nonwarming past climate simulations are incorporated in d4PDF along with the past climate simulations. The total data volume is approximately 2 petabytes. The atmospheric models satisfactorily simulate the past climate in terms of climatology, natural variations, and extreme events such as heavy precipitation and tropical cyclones. In addition, data users can obtain statistically significant changes in mean states or weather and climate extremes of interest between the past and future climates via a simple arithmetic computation without any statistical assumptions. The database is helpful in understanding future changes in climate states and in attributing past climate events to global warming. Impact assessment studies for climate changes have concurrently been performed in various research areas such as natural hazard, hydrology, civil engineering, agriculture, health, and insurance. The database has now become essential for promoting climate and risk assessment studies and for devising climate adaptation policies. Moreover, it has helped in establishing an interdisciplinary research community on global warming across Japan.

scholarly journals High-Resolution Monitoring and Assessment of Evapotranspiration and Gross Primary Production Using Remote Sensing in a Typical Arid Region

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Junxia Yan ◽  
Yanfei Ma ◽  
Dongyun Zhang ◽  
Zechen Li ◽  
Weike Zhang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Land Surface ◽  
Arid Region ◽  
Management Practices ◽  
Gross Primary Production ◽  
Irrigation District ◽  
Heihe River ◽  
Freshwater Resource ◽  
Oasis Area

Land surface evapotranspiration (ET) and gross primary productivity (GPP) are critical components in terrestrial ecosystems with water and carbon cycles. Large-scale, high-resolution, and accurately quantified ET and GPP values are important fundamental data for freshwater resource management and help in understanding terrestrial carbon and water cycles in an arid region. In this study, the revised surface energy balance system (SEBS) model and MOD17 GPP algorithm were used to estimate daily ET and GPP at 100 m resolution based on multi-source satellite remote sensing data to obtain surface biophysical parameters and meteorological forcing data as input variables for the model in the midstream oasis area of the Heihe River Basin (HRB) from 2010 to 2016. Then, we further calculated the ecosystem water-use efficiency (WUE). We validated the daily ET, GPP, and WUE from ground observations at a crop oasis station and conducted spatial intercomparisons of monthly and annual ET, GPP, and WUE at the irrigation district and cropland oasis scales. The site-level evaluation results show that ET and GPP had better performance than WUE at the daily time scale. Specifically, the deviations in the daily ET, GPP, and WUE data compared with ground observations were small, with a root mean square error (RMSE) and mean absolute percent error (MAPE) of 0.75 mm/day and 26.59%, 1.13 gC/m2 and 36.62%, and 0.50 gC/kgH2O and 39.83%, respectively. The regional annual ET, GPP, and WUE varied from 300 to 700 mm, 200 to 650 gC/m2, and 0.5 to 1.0 gC/kgH2O, respectively, over the entire irrigation oasis area. It was found that annual ET and GPP were greater than 550 mm and 500 gC/m2, and annual oasis cropland WUE had strong invariability and was maintained at approximately 0.85 gC/kgH2O. The spatial intercomparisons from 2010 to 2016 revealed that ET had similar spatial patterns to GPP due to tightly coupled carbon and water fluxes. However, the WUE spatiotemporal patterns were slightly different from both ET and GPP, particularly in the early and late growing seasons for the oasis area. Our results demonstrate that spatial full coverage and reasonably fine spatiotemporal variation and variability could significantly improve our understanding of water-saving irrigation strategies and oasis agricultural water management practices in the face of water shortage issues.

High-Resolution Climate Change Impact Analysis on Expected Future Water Availability in the Upper Jordan Catchment and the Middle East

2014 ◽  
Vol 15 (4) ◽  
pp. 1517-1531 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann ◽  
Andreas Heckl
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Water Availability ◽  
Impact Analysis ◽  
River Flow ◽  
Climate Model ◽  
Mesoscale Model ◽  
Global Climate Model ◽  
Full Range ◽  
The Impact

Abstract The impact of climate change on the future water availability of the upper Jordan River (UJR) and its tributaries Dan, Snir, and Hermon located in the eastern Mediterranean is evaluated by a highly resolved distributed approach with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) run at 18.6- and 6.2-km resolution offline coupled with the Water Flow and Balance Simulation Model (WaSiM). The MM5 was driven with NCEP reanalysis for 1971–2000 and with Hadley Centre Coupled Model, version 3 (HadCM3), GCM forcings for 1971–2099. Because only one regional–global climate model combination was applied, the results may not give the full range of possible future projections. To describe the Dan spring behavior, the hydrological model was extended by a bypass approach to allow the fast discharge components of the Snir to enter the Dan catchment. Simulation results for the period 1976–2000 reveal that the coupled system was able to reproduce the observed discharge rates in the partially karstic complex terrain to a reasonable extent with the high-resolution 6.2-km meteorological input only. The performed future climate simulations show steadily rising temperatures with 2.2 K above the 1976–2000 mean for the period 2031–60 and 3.5 K for the period 2070–99. Precipitation trends are insignificant until the middle of the century, although a decrease of approximately 12% is simulated. For the end of the century, a reduction in rainfall ranging between 10% and 35% can be expected. Discharge in the UJR is simulated to decrease by 12% until 2060 and by 26% until 2099, both related to the 1976–2000 mean. The discharge decrease is associated with a lower number of high river flow years.

scholarly journals Abrupt climate changes during Termination III in Southern Europe

2017 ◽  
Vol 114 (38) ◽  
pp. 10047-10052 ◽  
Author(s):  
Carlos Pérez-Mejías ◽  
Ana Moreno ◽  
Carlos Sancho ◽  
Miguel Bartolomé ◽  
Heather Stoll ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Availability ◽  
Climate Changes ◽  
Late Quaternary ◽  
Marine Isotope Stage ◽  
Southern Europe ◽  
Vegetation Productivity ◽  
Common Features ◽  
Sequence Of Events ◽  
Millennial Scale

The Late Quaternary glacial–interglacial transitions represent the highest amplitude climate changes over the last million years. Unraveling the sequence of events and feedbacks at Termination III (T-III), including potential abrupt climate reversals similar to those of the last Termination, has been particularly challenging due to the scarcity of well-dated records worldwide. Here, we present speleothem data from southern Europe covering the interval from 262.7 to 217.9 kyBP, including the transition from marine isotope stage (MIS) 8 to MIS 7e. High-resolution δ13C, δ18O, and Mg/Ca profiles reveal major millennial-scale changes in aridity manifested in changing water availability and vegetation productivity. uranium–thorium dates provide a solid chronology for two millennial-scale events (S8.1 and S8.2) which, compared with the last two terminations, has some common features with Heinrich 1 and Heinrich 2 in Termination I (T-I).

scholarly journals ORCHIDEE-ROUTING: A new river routing scheme using a high resolution hydrological database

2018 ◽  
Author(s):  
Trung Nguyen-Quang ◽  
Jan Polcher ◽  
Agnès Ducharne ◽  
Thomas Arsouze ◽  
Xudong Zhou ◽  
...  
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
River Flow ◽  
Anthropogenic Impacts ◽  
Computational Cost ◽  
Land Surface Model ◽  
Surface Model ◽  
Routing Scheme ◽  
Wide Range ◽  
River Routing

Abstract. This study presents a revised river routing scheme (RRS) for the Organising Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) land surface model. The revision is carried out to benefit from the high resolution topography provided the Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales (HydroSHEDS), processed to a resolution of approximately 1 kilometer. The RRS scheme of the ORCHIDEE uses a unit-to-unit routing concept which allows to preserve as much of the hydrological information of the HydroSHEDS as the user requires. The evaluation focuses on 12 rivers of contrasted size and climate which contribute freshwater to the Mediterranean Sea. First, the numerical aspect of the new RRS is investigated, to identify the practical configuration offering the best trade-off between computational cost and simulation quality for ensuing validations. Second, the performance of the revised scheme is evaluated against observations at both monthly and daily timescales. The new RRS captures satisfactorily the seasonal variability of river discharges, although important biases come from the water budget simulated by the ORCHIDEE model. The results highlight that realistic streamflow simulations require accurate precipitation forcing data and a precise river catchment description over a wide range of scales, as permitted by the new RRS. Detailed analyses at the daily timescale show promising performances of this high resolution RRS for replicating river flow variation at various frequencies. Eventually, this RRS is well adapted for further developments in the ORCHIDEE land surface model to assess anthropogenic impacts on river processes (e.g. damming for irrigation operation).

scholarly journals Dampak Perubahan Iklim Terhadap Debit Andalan Sungai Krueng Aceh

2016 ◽  
Vol 9 (1) ◽  
pp. 50-61
Author(s):  
Teuku Ferijal ◽  
Mustafril Mustafril ◽  
Dewi Sri Jayanti
Keyword(s):  
Climate Changes ◽  
River Flow ◽  
Daily Precipitation ◽  
Balance Model ◽  
Monthly Precipitation ◽  
Variable Infiltration Capacity ◽  
Dry Period ◽  
Infiltration Capacity ◽  
Hydrological Data ◽  
Daily Streamflow

Abstrak. Perubahan iklim yang menyebabkan perubahan karakteristik curah hujan berdampak pada aliran sungai. Penelitian ini bertujuan untuk menganalisa dampak perubahan iklim terhadap debit andalan. Data-data yang digunakan dalam penelitian ini adalah data klimatologi dan hidrologi yang semuanya dikumpulkan dari stasiun-stasiun yang ada dalam wilayah penelitian yaitu DAS Krueng Aceh. Model kesetimbangan air variable infiltration capacity digunakan dalam penelitian ini untuk menghitung debit sungai harian berdasarkan data curah hujan dan evapotranspirasi harian. Hasil analisa menunjukkan bahwa suhu udara tahunan rata-rata DAS Krueng Aceh telah mengalami peningkatan yang drastis sebesar 0,6°C sejak tahun 2001. Perubahan tersebut juga diikuti dengan adanya tren peningkatan curah hujan (22%) pada bulan-bulan basah (November-Januari) serta penurunan curah hujan (26%) pada bulan-bulan kering (Mei-Agustus). Dampak dari perubahan iklim tersebut adalah terjadinya penurunan debit sungai Krueng Aceh yang ditandai semakin meningkatnya kemungkinan debit aliran lebih kecil dari 18,77 m3/s dan menurunkan debit andalan terutama pada periode April-Desember sebesar 23,5%.  Impact of Climate Change on Dependable Discharge in the Krueng Aceh River Abstract. Climate changes altering precipitation characteristic bring impact on streamflow. This research aims to analyze impact of climate changes on dependable discharge. Climatological and hydrological data were collected from stations within Krueng Aceh Watershed. Variable infiltration capacity water balance model was applied to calculate daily streamflow base on daily precipitation and evapotranspiration. The results suggested that annual air temperature of Krueng Aceh Watershed has been squally increasing 0.6°C since 2001. The changes were also detected on monthly precipitation i.e. a 22% increase in wet period (November-January) and a 26% decrease in dry period (Mei-August). The changes have impacted the Krueng Aceh River flow by increasing possibility of flow lower than 18.77m3/s and decreasing dependable discharge by 23.5% for period of April-December.

scholarly journals Using an Isohaline Flux Analysis to Predict the Salt Content in an Unsteady Estuary

2017 ◽  
Vol 47 (11) ◽  
pp. 2811-2828 ◽  
Author(s):  
Matthew D. Rayson ◽  
Edward S. Gross ◽  
Robert D. Hetland ◽  
Oliver B. Fringer
Keyword(s):  
River Flow ◽  
Salt Content ◽  
Box Model ◽  
Flux Analysis ◽  
Galveston Bay ◽  
Exchange Flow ◽  
Salt Intrusion ◽  
Adjustment Time ◽  
The Mean ◽  
Salinity Difference

AbstractAn estuary is classified as unsteady when the salinity adjustment time is longer than the forcing time scale. Predicting salt content or salt intrusion length using scaling arguments based on a steady-state relationship between flow and salinity is inaccurate in these systems. In this study, a time-dependent salinity box model based on an unsteady Knudsen balance is used to demonstrate the effects of river flow, inward total exchange flow (tidal plus steady), and the salinity difference between inflow and outflow on the salt balance. A key component of the box model is a relationship that links the normalized difference between inflowing and outflowing salinity at the mouth and the mean salinity content. The normalized salinity difference is shown to be proportional to the mean salinity squared, based on theoretical arguments from the literature. The box model is validated by hindcasting 5 years of mean salinity in Galveston Bay (estimated from coarse observations) in response to highly variable river discharge. It is shown that this estuary typically has a long adjustment time relative to the forcing time scales, and, therefore, the volume-averaged salinity rarely reaches equilibrium. The box model highlights the reasons why the adjustment time in a large, partially mixed estuary like Galveston Bay is slower when the mean salt content is higher. Furthermore, it elucidates why the salt content in the estuary is more responsive to changes in river flow than in landward exchange flow at the estuary mouth, even though the latter quantity is usually several times larger.

scholarly journals Uncertainty analysis of hydrological ensemble forecasts in a distributed model utilising short-range rainfall prediction

2009 ◽  
Vol 13 (3) ◽  
pp. 293-303 ◽  
Author(s):  
Y. Xuan ◽  
I. D. Cluckie ◽  
Y. Wang
Keyword(s):  
High Resolution ◽  
Short Range ◽  
River Flow ◽  
Hydrological Model ◽  
Uncertainty Propagation ◽  
Weather Forecast ◽  
Distributed Model ◽  
Distributed Hydrological Model ◽  
Weather System ◽  
Considerable Uncertainty

Abstract. Advances in mesoscale numerical weather predication make it possible to provide rainfall forecasts along with many other data fields at increasingly higher spatial resolutions. It is currently possible to incorporate high-resolution NWPs directly into flood forecasting systems in order to obtain an extended lead time. It is recognised, however, that direct application of rainfall outputs from the NWP model can contribute considerable uncertainty to the final river flow forecasts as the uncertainties inherent in the NWP are propagated into hydrological domains and can also be magnified by the scaling process. As the ensemble weather forecast has become operationally available, it is of particular interest to the hydrologist to investigate both the potential and implication of ensemble rainfall inputs to the hydrological modelling systems in terms of uncertainty propagation. In this paper, we employ a distributed hydrological model to analyse the performance of the ensemble flow forecasts based on the ensemble rainfall inputs from a short-range high-resolution mesoscale weather model. The results show that: (1) The hydrological model driven by QPF can produce forecasts comparable with those from a raingauge-driven one; (2) The ensemble hydrological forecast is able to disseminate abundant information with regard to the nature of the weather system and the confidence of the forecast itself; and (3) the uncertainties as well as systematic biases are sometimes significant and, as such, extra effort needs to be made to improve the quality of such a system.

Continental-Scale River Flow Modeling of the Mississippi River Basin Using High-Resolution NHDPlusDataset

2016 ◽  
Vol 53 (2) ◽  
pp. 258-279 ◽  
Author(s):  
Ahmad A. Tavakoly ◽  
Alan D. Snow ◽  
Cédric H. David ◽  
Michael L. Follum ◽  
David R. Maidment ◽  
...  
Keyword(s):  
High Resolution ◽  
River Basin ◽  
Mississippi River ◽  
River Flow ◽  
Mississippi River Basin ◽  
Flow Modeling ◽  
Continental Scale
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