scholarly journals A CMIP6 ensemble for downscaled monthly climate normals over North America

2021 ◽  
Author(s):  
Colin Mahony ◽  
Tongli Wang ◽  
Andreas Hamann ◽  
Alex Cannon
Keyword(s):  
North America ◽  
Temporal Resolution ◽  
Climate Model ◽  
Regional Analysis ◽  
Climate Change Impacts ◽  
High Temporal Resolution ◽  
Screening Criteria ◽  
Very High Spatial Resolution ◽  
Very High ◽  
Selection Of

Many studies of climate change impacts and adaptation use climate model projections downscaled at very high spatial resolution (~1km) but very low temporal resolution (20- to 30-year normals). These applications have model selection priorities that are distinct from analyses at high temporal resolution. Here, we select a 13-model CMIP6 ensemble designed for robust change-factor downscaling of monthly climate normals and describe its attributes in North America. The ensemble is representative of the distribution of equilibrium climate sensitivity and grid resolution in the CMIP6 generation. We provide rationale for a 9-member subset of the ensemble based on screening criteria and sequence these 9 models for selection of smaller ensembles for regional analysis. Although we have focused our documentation on North America, the 13-model ensemble is selected using global criteria and applicable to downscaling climate normals in other continents.

scholarly journals Streamflow-based evaluation of climate model sub-selection methods

2020 ◽  
Vol 163 (3) ◽  
pp. 1267-1285 ◽  
Author(s):  
Jens Kiesel ◽  
Philipp Stanzel ◽  
Harald Kling ◽  
Nicola Fohrer ◽  
Sonja C. Jähnig ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Historical Data ◽  
Model Performance ◽  
Climate Change Impacts ◽  
Climate Impact ◽  
Selection Method ◽  
Danube River ◽  
Selection Methods ◽  
Selection Of

AbstractThe assessment of climate change and its impact relies on the ensemble of models available and/or sub-selected. However, an assessment of the validity of simulated climate change impacts is not straightforward because historical data is commonly used for bias-adjustment, to select ensemble members or to define a baseline against which impacts are compared—and, naturally, there are no observations to evaluate future projections. We hypothesize that historical streamflow observations contain valuable information to investigate practices for the selection of model ensembles. The Danube River at Vienna is used as a case study, with EURO-CORDEX climate simulations driving the COSERO hydrological model. For each selection method, we compare observed to simulated streamflow shift from the reference period (1960–1989) to the evaluation period (1990–2014). Comparison against no selection shows that an informed selection of ensemble members improves the quantification of climate change impacts. However, the selection method matters, with model selection based on hindcasted climate or streamflow alone is misleading, while methods that maintain the diversity and information content of the full ensemble are favorable. Prior to carrying out climate impact assessments, we propose splitting the long-term historical data and using it to test climate model performance, sub-selection methods, and their agreement in reproducing the indicator of interest, which further provide the expectable benchmark of near- and far-future impact assessments. This test is well-suited to be applied in multi-basin experiments to obtain better understanding of uncertainty propagation and more universal recommendations regarding uncertainty reduction in hydrological impact studies.

A Strategy for Scaling ERA5 Sea Winds Using Climate Model Data

2020 ◽  
Author(s):  
Silvio Davison ◽  
Francesco Barbariol ◽  
Alvise Benetazzo ◽  
Luigi Cavaleri ◽  
Paola Mercogliano
Keyword(s):  
Temporal Resolution ◽  
Climate Model ◽  
Grid Point ◽  
High Temporal Resolution ◽  
Widespread Application ◽  
Northern Adriatic ◽  
Wind Speeds ◽  
The Past ◽  
Statistical Strategy ◽  
Resolution Data

<p>Over the past decade, reanalysis data products have found widespread application in many areas of research and have often been used for the assessment of the past and present climate. They produce reliable atmospheric fields at high temporal resolution, albeit at low-to-mid spatial resolution. On the other hand, climatological analyses, quite often down-scaled to represent conditions also in enclosed basins, lack the historical sequence of stormy events and are often provided at poor temporal resolution.</p><p>In this context, we investigated the possibility of using the ERA5 reanalysis 10-m wind (25-km and 1-hour resolution data) to assess the Mediterranean Sea wind climate (past and scenario). We propose a statistical strategy to relate ERA5 wind speeds over the sea to the past and future wind speeds produced by the COSMO-CLM (8-km and 6-hour resolution data) climatological model. In particular, the probability density function of the ERA5 wind speed at each grid point is adjusted to match that of COSMO-CLM. In this way, past ERA5 winds are corrected to account for the COSMO-CLM energy, while ERA5 scaled wind sequence can be projected in the future with COSMO-CLM scenario energy. Comparison with past observations confirms the validity of the adopted method.</p><p>In the Venezia2021 project, we have applied this strategy for the assessment of the changing wind and, after WAVEWATCH III model runs, also the wave climate in the Northern Adriatic Sea, especially in front of Venice and the MOSE barriers, under two IPCC (RCP 4.5 and 8.5) scenarios.</p><p>In general, this strategy may be applied to produce a scaled wind dataset in enclosed basins and improve past wave modeling applications based on any reanalysis wind data.</p>

scholarly journals Brief Communication: The interaction of clouds with surface latent heat flux variation before the 2011 <i>M</i> = 6.1 Russia earthquake

2014 ◽  
Vol 14 (9) ◽  
pp. 2649-2653 ◽  
Author(s):  
Y. Jie ◽  
G. Guangmeng
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Temporal Resolution ◽  
Satellite Images ◽  
High Temporal Resolution ◽  
Flux Variation ◽  
Surface Latent Heat Flux ◽  
First Time ◽  
Very High

Abstract. Recently, surface latent heat flux (SLHF) data have been widely used to study the anomalies before earthquakes. Most studies use the daily SLHF data. Here we use both the daily SLHF data and the high temporal resolution (four times one day) SLHF data, and compare the SLHF changes with satellite cloud images at the first time. We check the data from 1 September to 30 October 2011, and the result shows that there is really a very high SLHF anomaly (more than 2σ) in the epicenter area just 5 days before the M = 6.1 Russia earthquake that occurred on 14 October 2011. It should be considered as a preseismic precursor if judged with previously published methods, but our comparison between SLHF change and satellite images shows that the SLHF anomaly is contaminated by a thick cloud. It is difficult to verify that this SLHF anomaly is caused by an earthquake and our analysis shows that it is more related to meteorological reason. This example tells us that scientists must know the data's meaning before they use it; if not, they may draw a wrong conclusion. Based on this example, we suggest that previously published SLHF anomalies before earthquakes should be reanalyzed with our method to exclude the false anomalies.

Ground-Based Passive Microwave Profiling during Dynamic Weather Conditions

2009 ◽  
Vol 26 (6) ◽  
pp. 1057-1073 ◽  
Author(s):  
K. R. Knupp ◽  
T. Coleman ◽  
D. Phillips ◽  
R. Ware ◽  
D. Cimini ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Microwave Radiometer ◽  
Ground Level ◽  
Weather Conditions ◽  
Squall Line ◽  
High Temporal Resolution ◽  
Short Period ◽  
Potential Benefits ◽  
Operational Activities ◽  
Very High

Abstract Short-period (1–5 min) temperature and humidity soundings up to 10-km height are retrieved from ground-based 12-channel microwave radiometer profiler (MWRP) observations. In contrast to radiosondes, the radiometric retrievals provide very high temporal resolution (1 min or less) of thermodynamic profiles, but the vertical resolution, which declines in proportion to the height above ground level, is lower. The high temporal resolution is able to resolve detailed meso-γ-scale thermodynamic and limited microphysical features of various rapidly changing mesoscale and/or hazardous weather phenomena. To illustrate the MWRP capabilities and potential benefits to research and operational activities, the authors present example radiometric retrievals from a variety of dynamic weather phenomena including upslope supercooled fog, snowfall, a complex cold front, a nocturnal bore, and a squall line accompanied by a wake low and other rapid variations in low-level water vapor and temperature.

scholarly journals Climate change impacts on thermal growing conditions of Portuguese grapevine varieties

2018 ◽  
Vol 50 ◽  
pp. 01030
Author(s):  
João A. Santos ◽  
Ricardo Costa ◽  
Helder Fraga
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Heat Accumulation ◽  
Adaptation Measures ◽  
Growing Degree Hours ◽  
Ensemble Mean ◽  
Very High Spatial Resolution ◽  
Growing Conditions ◽  
Consistent Information ◽  
Very High

Heat accumulation conditions of a collection of 44 grapevine cultivars currently grown in Portugal are assessed at very high spatial resolution (~1 km) and for 1981–2015. A Growing Degree Hours – GDH (February–October) index is used for this purpose. Three clusters of grapevine cultivars are identified, assembling varieties with close heat accumulation requirements (early, intermediate and late ripening). These clusters provide more physiologically consistent information when compared to previous studies, as non-linear plant-temperature relationships are herein taken into account. For the future climates in Portugal, ensemble mean projections under two anthropogenic-driven scenarios (RCP4.5 and RCP8.5, 2041–2070), from four EURO-CORDEX simulations, reveal a widespread increase of GDH, but with spatial heterogeneities. The spatial variability throughout Portugal is projected to decrease in GDH, with strongest increases in the coolest regions of the northeast. The typical heat accumulation conditions of each cluster are projected to gradually shift north-eastwards and to higher-elevation areas. An unprecedented level of detail for a large collection of grapevine varieties in Portugal is provided, which may promote a better planning of climate change adaptation measures in Portuguese viticulture.

scholarly journals Cubesats Allow High Spatiotemporal Estimates of Satellite-Derived Bathymetry

2019 ◽  
Vol 11 (11) ◽  
pp. 1299 ◽  
Author(s):  
Dimitris Poursanidis ◽  
Dimosthenis Traganos ◽  
Nektarios Chrysoulakis ◽  
Peter Reinartz
Keyword(s):  
Temporal Resolution ◽  
Satellite Remote Sensing ◽  
High Spatial Resolution ◽  
Empirical Method ◽  
High Temporal Resolution ◽  
Coastal Marine ◽  
Daily Data ◽  
Marine Areas ◽  
Silver Bullet ◽  
Selection Of

High spatial and temporal resolution satellite remote sensing estimates are the silver bullet for monitoring of coastal marine areas globally. From 2000, when the first commercial satellite platforms appeared, offering high spatial resolution data, the mapping of coastal habitats and the extraction of bathymetric information have been possible at local scales. Since then, several platforms have offered such data, although not at high temporal resolution, making the selection of suitable images challenging, especially in areas with high cloud coverage. PlanetScope CubeSats appear to cover this gap by providing their relevant imagery. The current study is the first that examines the suitability of them for the calculation of the Satellite-derived Bathymetry. The availability of daily data allows the selection of the most qualitatively suitable images within the desired timeframe. The application of an empirical method of spaceborne bathymetry estimation provides promising results, with depth errors that fit to the requirements of the International Hydrographic Organization at the Category Zone of Confidence for the inclusion of these data in navigation maps. While this is a pilot study in a small area, more studies in areas with diverse water types are required for solid conclusions on the requirements and limitations of such approaches in coastal bathymetry estimations.

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