The Outer Continental Shelf along the U.S. east coast exhibits abundant wind resources and is now a geographic focus for offshore wind deployments. This analysis derives and presents expected extreme ...wind and wave conditions for the sixteen lease areas that are currently being developed. Using the homogeneous ERA5 reanalysis dataset it is shown that the fifty-year return period wind speed (U50) at 100 m a.s.l. in the lease areas ranges from 29.2 to 39.7 ms−1. After applying corrections to account for spectral smoothing and averaging period, the associated pseudo-point U50 estimates are 34 to 46 ms−1. The derived uncertainty in U50 estimates due to different distributional fitting is smaller than the uncertainty associated with under-sampling of the interannual variability in annual maximum wind speeds. It is shown that, in the northern lease areas, annual maximum wind speeds are generally associated with intense extratropical cyclones rather than cyclones of tropical origin. Extreme wave statistics are also presented and indicate that the 50-year return period maximum wave height may substantially exceed 15 m. From this analysis, there is evidence that annual maximum wind speeds and waves frequently derive from the same cyclone source and often occur within a 6 h time interval.
Given the importance of aerosol particles to radiative transfer via aerosol-radiation interactions, a methodology for tracking and diagnosing causes of temporal changes in regional-scale aerosol ...populations is illustrated. The aerosol optical properties tracked include estimates of total columnar burden (aerosol optical depth, AOD), dominant size mode (Ångström exponent, AE), and relative magnitude of radiation scattering versus absorption (single scattering albedo, SSA), along with metrics of the structure of the spatial field of these properties. Over well-defined regions of North America, there are generally negative temporal trends in mean and extreme AOD, and SSA. These are consistent with lower aerosol burdens and transition towards a relatively absorbing aerosol, driven primarily by declining sulfur dioxide emissions. Conversely, more remote regions are characterized by increasing mean and extreme AOD that is attributed to increased local wildfire emissions and long-range (transcontinental) transport. Regional and national reductions in anthropogenic emissions of aerosol precursors are leading to declining spatial autocorrelation in the aerosol fields and increased importance of local anthropogenic emissions in dictating aerosol burdens. However, synoptic types associated with high aerosol burdens are intensifying (becoming more warm and humid), and thus changes in synoptic meteorology may be offsetting aerosol burden reductions associated with emissions legislation.
Projected changes to the El Niño Southern Oscillation (ENSO) climate mode have been explored using global Earth system models (ESMs). Regional expressions of such changes have yet to be fully ...advanced and may require the use of regional downscaling. Here, we employ regional climate modeling (RCM) using the Weather Research and Forecasting (WRF) model at convection-permitting resolution and nested in output from the HadGEM2 ESM. We quantify ENSO teleconnections to temperature and precipitation anomalies in historical and future climate scenarios over eastern North America. Two paired simulations are run, a strong El Niño (positive ENSO phase) and a weak La Niña (negative ENSO phase), for the historical and future years. The HadGEM2 direct output and HadGEM2-WRF simulation output are compared to the anomalies derived from the NOAA ENSO Climate Normals dataset. The near-surface temperature and precipitation differences by ENSO phase, as represented by the HadGEM2-WRF historical simulations, show a poor degree of association with the NOAA ENSO Climate Normals, in part because of the large biases in the HadGEM2 model. Downscaling with the WRF model does improve the agreement with the observations, and large discrepancies remain. The model chain HadGEM2-WRF reverses the sign of the ENSO phase response over eastern North America under simulations of the future climate with high greenhouse gas forcing, but due to the poor agreement with the NOAA ENSO Climate Normals it is difficult to assign confidence to this prediction.
Leading edge erosion of wind turbine blades is a significant source of loss of energy production in some wind farms. The extent of erosion appears to be controlled, at least in part by local ...meteorological conditions; specifically, by the accumulated kinetic energy transfer from collisions with falling hydrometeors (precipitation). However, the aerodynamics of flow around wind turbine blades means not all falling hydrometeors will impact the blade, and at least in principle some will be sufficiently small to follow the streamlines and thus avoid collisions with the rotating blades. Here we present the setup for computational fluid dynamics (CFD) simulations designed to quantify collision efficiency as a function of hydrometeor size for a simplified three-blade turbine using ANSYS Fluent 19.2 as the main numerical solver. The simulations correctly reproduce the pressure variability across the blade and illustrate that the variations in the droplet-blade collision probability is a function of wind speed, rain intensity and droplet diameter.
In climate science and applications, the term “metric” is used to describe the distillation of complex, multifaceted evaluations to summarize the overall quality of a model simulation, or other data ...product, and/or as a means to quantify some response to climate change. Metrics provide insights into the fidelity of processes and outcomes from climate models and can assist with both differentiating models' representation of variables or processes and informing whether models are “fit for purpose.” Metrics can also provide a valuable reference point for co‐production of knowledge between climate scientists and climate impact practitioners. Although continued metric developments enable model developers to better understand the impacts of decisions made in the model design process, metrics also have implications for the characterization of uncertainty and facilitating analyses of underlying physical processes. As a result, comprehensive evaluation with multiple metrics enhances usability of climate information by both scientific and stakeholder communities. This paper presents examples of insights gained from the development and appropriate use of metrics, and provides examples of how metrics can be used to engage with stakeholders and inform decision‐making.
This article is categorized under:
Climate Models and Modeling > Knowledge Generation with Models
The Social Status of Climate Change Knowledge > Climate Science and Decision Making
Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate Change
Metrics are essential tools within climate science. When climate scientists and climate impact practitioners co‐design metrics then climate science and decision‐making can both be advanced.
MONITORING AND UNDERSTANDING CHANGES IN EXTREMES Vose, Russell S.; Applequist, Scott; Bourassa, Mark A. ...
Bulletin of the American Meteorological Society,
03/2014, Volume:
95, Issue:
3
Journal Article
Peer reviewed
Open access
This scientific assessment examines changes in three climate extremes—extratropical storms, winds, and waves—with an emphasis on U.S. coastal regions during the cold season. There is moderate ...evidence of an increase in both extratropical storm frequency and intensity during the cold season in the Northern Hemisphere since 1950, with suggestive evidence of geographic shifts resulting in slight upward trends in offshore/coastal regions. There is also suggestive evidence of an increase in extreme winds (at least annually) over parts of the ocean since the early to mid-1980s, but the evidence over the U.S. land surface is inconclusive. Finally, there is moderate evidence of an increase in extreme waves in winter along the Pacific coast since the 1950s, but along other U.S. shorelines any tendencies are of modest magnitude compared with historical variability. The data for extratropical cyclones are considered to be of relatively high quality for trend detection, whereas the data for extreme winds and waves are judged to be of intermediate quality. In terms of physical causes leading to multidecadal changes, the level of understanding for both extratropical storms and extreme winds is considered to be relatively low, while that for extreme waves is judged to be intermediate. Since the ability to measure these changes with some confidence is relatively recent, understanding is expected to improve in the future for a variety of reasons, including increased periods of record and the development of “climate reanalysis” projects.
The technical potential offshore wind resource greatly exceeds current electricity use. However, areas suitable for bottom-mounted wind turbines close to large coastal demand centers are limited. ...Thus, an increasing number of offshore wind farms will operate in the wake (or wind shadow) of other wind farms. Maximizing system-wide electricity production and overall energy extraction from offshore wind, while being cognizant of other constraints, requires optimal siting of offshore wind energy lease areas to minimize ‘wind theft’ resulting from wakes generated by upstream wind turbine arrays. Uniquely detailed high-resolution simulations are performed with two different wind farm wake parameterizations to quantify power generation and wake-induced power losses from all offshore wind energy lease areas along the U.S. east coast. Annual Energy Production (AEP) from current leases is projected to be 139 to 173 TWh/yr. However, whole wind farm wakes extend over two to three times the footprint of existing lease areas. Those wakes from both local and remote wind turbines are projected to reduce the AEP by 15 to 49 TWh/yr. The simulation output is also used with new, robust, innovative tools to generate georeferenced data layers describing whole wind farm wakes (wind shadows) for use in planning and development. It is shown that wind shadows (wake reduction of wind speed) from the existing lease areas degrade the wind resource in up to 25% of the unleased area available after selecting areas with a good wind resource (mean wind speed >8.2 ms−1) and applying restrictions for water depth, distance to shore and to avoid busy shipping lanes. These results demonstrate the value of efforts to reduce wake losses to maximize power production efficiency. They also emphasize the importance of considering wakes in multi-criteria analyses to identify new lease areas for auction and for determining the resulting purchase price.
•Uncoordinated wind turbine deployments offshore reduces system-wide power production, increasing LCoE.•Offshore wind farm wakes extend over areas that are many times the wind farm footprints.•Wind shadows generated by operating wind farms reduce the wind resource in other lease areas.•Wake effects will reduce electricity production from planned US east coast offshore wind farms by up to 48.5 TWh/yr.•Robust methods for generating georeferenced data layers describing wake extents are presented.
Thank You to Our 2023 Reviewers Caprarelli, Graziella; Baratoux, David; Cervato, Cinzia ...
Earth and space science (Hoboken, N.J.),
April 2024, 2024-04-00, 20240401, 2024-04-01, Volume:
11, Issue:
4
Journal Article
Peer reviewed
Open access
The Editors and Staff of Earth and Space Science thank the reviewers whose selfless work has significantly contributed to the publication process of papers highlighting the best research in ...geophysics, planetary, and space science in 2023. Peer‐reviewing is a demanding and thankless job. It is however an essential component of the scientific process, requiring the highest standards of integrity and rigor. Reviewers check data and procedures and test reproducibility of methods and results; they share their expertise to verify that the interpretations and conclusions of a paper are consistent with assumptions and existing knowledge. Without this essential work it would not be possible to trust in the scientific process. Publication of papers in a multidisciplinary journal such as Earth and Space Science, that highlights methods, instruments, data and algorithms, relies directly on the expertise of its reviewers to verify and vouch for the quality of the papers that are published. We are indebted to all our reviewers and are delighted to acknowledge them publicly in this Editorial.
Plain Language Summary
The Editors and Staff of Earth and Space Science acknowledge the importance of hundreds of peer reviewers who contributed to the scientific rigor of the papers published in the journal. The Editors wish to publicly recognize the 926 reviewers who gave selflessly of their time and expertise in 2023.
Key Points
The editors thank the 2023 peer reviewers
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