scholarly journals Summer Covariability of Surface Climate for Renewable Energy across the Contiguous United States: Role of the North Atlantic Subtropical High

2018 ◽  
Vol 57 (12) ◽  
pp. 2749-2768 ◽  
Author(s):  
Kenji Doering ◽  
Scott Steinschneider
Keyword(s):  
United States ◽  
Renewable Energy ◽  
North Atlantic ◽  
Energy Demand ◽  
Large Scale ◽  
Wind Speeds ◽  
North Atlantic Subtropical High ◽  
The North ◽  
Surface Climate ◽  
The North Atlantic

AbstractThis study examines the joint spatiotemporal variability of summertime climate linked to renewable energy sources (precipitation and streamflow, wind speeds, and insolation) and energy demand drivers (temperature, relative humidity, and a heat index) across the contiguous United States (CONUS) between 1948 and 2015. Canonical correlation analysis is used to identify the primary modes of joint variability between wind speeds and precipitation and related patterns of the other hydrometeorological variables. The first two modes exhibit a pan-U.S. dipole with lobes in the eastern and central CONUS. Composite analysis shows that these modes are directly related to the displacement of the western ridge of the North Atlantic subtropical high (NASH), suggesting that a single, large-scale feature of atmospheric circulation drives much of the large-scale climate covariability related to summertime renewable energy supply and demand across the CONUS. The impacts of this climate feature on the U.S. energy system are shown more directly by examining changes in surface climate variables at existing and potential sites of renewable energy infrastructure and locations of high energy demand. Also, different phases of the NASH are related to concurrent and lagged modes of oceanic and atmospheric climate variability in the Pacific and Atlantic Ocean basins, with results suggesting that springtime climate over both oceans may provide some potential to predict summer variability in the NASH and its associated surface climate. The implications of these findings for the impacts of climate variability and change on integrated renewable energy systems over the CONUS are discussed.

Seasonal Predictability of Wintertime mid-latitude Cyclonic Activity over the North Atlantic and Europe

2021 ◽  
Author(s):  
Alvise Aranyossy ◽  
Sebastian Brune ◽  
Lara Hellmich ◽  
Johanna Baehr
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Jet Stream ◽  
Cyclonic Activity ◽  
Max Planck ◽  
Pressure System ◽  
Wind Speeds ◽  
Average Lifespan ◽  
The North ◽  
The North Atlantic

<p>We analyse the connections between the wintertime North Atlantic Oscillation (NAO), the eddy-driven jet stream with the mid-latitude cyclonic activity over the North Atlantic and Europe. We investigate, through the comparison against ECMWF ERA5 and hindcast simulations from the Max Planck Institute Earth System Model (MPI-ESM), the potential for enhancement of the seasonal prediction skill of the Eddy Kinetic Energy (EKE) by accounting for the connections between large-scale climate and the regional cyclonic activity. Our analysis focuses on the wintertime months (December-March) in the 1979-2019 period, with seasonal predictions initialized every November 1st. We calculate EKE from wind speeds at 250 hPa, which we use as a proxy for cyclonic activity. The zonal and meridional wind speeds are bandpass filtered with a cut-off at 3-10 days to fit with the average lifespan of mid-latitude cyclones. </p><p>Preliminary results suggest that in ERA5, major positive anomalies in EKE, both in quantity and duration, are correlated with a northern position of the jet stream and a positive phase of the NAO. Apparently, a deepened Icelandic low-pressure system offers favourable conditions for mid-latitude cyclones in terms of growth and average lifespan. In contrast, negative anomalies in EKE over the North Atlantic and Central Europe are associated with a more equatorward jet stream, these are also linked to a negative phase of the NAO.  Thus, in ERA5, the eddy-driven jet stream and the NAO play a significant role in the spatial and temporal distribution of wintertime mid-latitude cyclonic activity over the North Atlantic and Europe. We extend this connection to the MPI-ESM hindcast simulations and present an analysis of their predictive skill of EKE for wintertime months.</p>

scholarly journals Influence of the North Atlantic Subtropical High on wet and dry sea-breeze events in North Carolina, United States

2017 ◽  
pp. 9 ◽  
Author(s):  
Nicholas T. Luchetti ◽  
Rosana Nieto Ferreira ◽  
Thomas M. Rickenbach ◽  
Mark R. Nissenbaum ◽  
Joel D. McAuliffe
Keyword(s):  
United States ◽  
North Carolina ◽  
North Atlantic ◽  
Convective Available Potential Energy ◽  
Sea Breeze ◽  
The United States ◽  
Subtropical High ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic

The sea-breeze (SB) is an important source of summertime precipitation in North Carolina (NC, southeast United States). However, not all SB events produce precipitation. A climatology of wet and dry SB events in NC is used to investigate the conditions that are conducive to precipitation associated with the sea breeze. Radar imagery was used to detect 88 SB events that occurred along the NC coast between May-September of 2009-2012. The majority (85%) of SB events occurred during offshore flow (53%) or during flow that was parallel to the coast (22%). SB events were separated into dry (53%) and wet (47%) events and differences in the dynamic and thermodynamic parameters of the environment in which they formed were analyzed. Significant differences in dynamic and thermodynamic conditions were found. SB dry events occurred under stronger winds (6.00 ± 2.36 ms-1) than SB wet events (4.02 ± 2.16 ms-1). Moreover, during SB wet events larger values of convective available potential energy and lower values of convective inhibition were present, conditions that favor precipitation. Overall, the SB wet events accounted for 20-30% of the May-September precipitation along the NC coastal region. The position of the North Atlantic Subtropical High (NASH) controls both moisture availability and winds along the NC coast, thus providing a synoptic-scale control mechanism for SB precipitation. In particular, it was shown that when the NASH western ridge is located along the southeast coast of the United States, it causes a moist southwesterly flow along the NC coast that may favor the occurrence of SB wet events.

Impacts of the North Atlantic Subtropical High on Daily Summer Precipitation over the Conterminous United States

2021 ◽  
Author(s):  
Enrico Zorzetto ◽  
Laifang Li
Keyword(s):  
United States ◽  
North Atlantic ◽  
Daily Rainfall ◽  
Summer Precipitation ◽  
Subtropical High ◽  
Rainfall Events ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic ◽  
The Impact

AbstractBy modulating the moisture flux from ocean to adjacent land, the North Atlantic Subtropical High (NASH) western ridge significantly influences summer-season total precipitation over the Conterminous United States (CONUS). However, its influence on the frequency and intensity of daily rainfall events over the CONUS remains unclear. Here we introduce a Bayesian statistical model to investigate the impacts of the NASH western ridge position on key statistics of daily-scale summer precipitation, including the intensity of rainfall events, the probability of precipitation occurrence, and the probability of extreme values. These statistical quantities play a key role in characterizing both the impact of wet extremes (e.g., the probability of floods) and dry extremes. By applying this model to historical rain gauge records (1948-2019) covering the entire CONUS, we find that the western ridge of the NASH influences the frequency of rainfall as well as the distribution of rainfall intensities over extended areas of the CONUS. In particular, we find that the NASH ridge also modulates the frequency of extreme rainfall, especially that over part of the Southeast and upper Midwest. Our analysis underlines the importance of including the NASH western ridge position as a predictor for key statistical rainfall properties to be used for hydrological applications. This result is especially relevant for projecting future changes in daily rainfall regimes over the CONUS based on the predicted strengthening of the NASH in a warming climate.

scholarly journals Projection of Summer Precipitation over the Southeastern United States in the Superparameterized CCSM4

2015 ◽  
Vol 28 (20) ◽  
pp. 8052-8066 ◽  
Author(s):  
Xiaojie Zhu ◽  
Cristiana Stan
Keyword(s):  
United States ◽  
Soil Moisture ◽  
North Atlantic ◽  
Hydrological Cycle ◽  
Southeastern United States ◽  
Summer Precipitation ◽  
Subtropical High ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic

Abstract Projections of the hydrological cycle over the southeastern United States are compared between CCSM4 and the superparameterized model (SP-CCSM4). Under the extreme forcing of the representative concentration pathway 8.5 (RCP8.5) climate change scenario, in Virginia, North Carolina, South Carolina, and Kentucky, SP-CCSM4 projects a decrease in summer precipitation, whereas the conventionally parameterized CCSM4 projects an increase in summer rainfall. The projected reduction in summer precipitation in SP-CCSM4 is due to the remote influence from the northwest intrusion of the North Atlantic subtropical high, as well as the local decrease of soil moisture content. Both models show that summer precipitation over the southern United States is characterized by a positive feedback with soil moisture. However, in CCSM4 rainfall increases with increasing soil moisture and in SP-CCSM4 rainfall decreases with decreasing soil moisture. The different representation of cloud processes in the two models yields different responses of precipitation to the latent heat flux changes over the southeastern United States. Moreover, multivariate EOF analyses in the two models suggest that the local land–atmosphere interactions have a stronger influence on the projected changes of precipitation over the southeastern United States than does the North Atlantic subtropical high.

scholarly journals Comments on “Changes to the North Atlantic Subtropical High and Its Role in the Intensification of Summer Rainfall Variability in the Southeastern United States”

2013 ◽  
Vol 26 (2) ◽  
pp. 679-682 ◽  
Author(s):  
Jeremy E. Diem
Keyword(s):  
United States ◽  
Global Warming ◽  
North Atlantic ◽  
Rainfall Variability ◽  
Southeastern United States ◽  
Summer Rainfall ◽  
Subtropical High ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic

Abstract In a recent article, Li et al. examined changes in the summer-season location of the western ridge of the North Atlantic subtropical high from 1948 to 2007 because there has been an increase in interannual summer rainfall variability in the southeastern United States. The following major conclusions by Li et al. are incorrect: the western ridge has undergone a significant westward trend since the late 1970s; the western ridge had increased meridional movement during 1978–2007 compared to 1948–1977; and global warming appears to be contributing to the westward expansion of the western ridge. Results presented in this paper reveal that the western ridge has been moving eastward over the past three decades, there was no change in latitudinal variance, and a westward movement of the western ridge should not be linked to global warming.

scholarly journals Springtime connections between the large-scale sea-level pressure field and gust wind speed over Iberia and the Balearics

2011 ◽  
Vol 11 (1) ◽  
pp. 191-203 ◽  
Author(s):  
M. L. Martín ◽  
F. Valero ◽  
A. Pascual ◽  
A. Morata ◽  
M. Y. Luna
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Large Scale ◽  
Pressure Field ◽  
Wind Gust ◽  
Sea Level Pressure ◽  
Wind Speeds ◽  
The North ◽  
Wind Gusts ◽  
The North Atlantic

Abstract. This paper investigates, by means of Singular Value Decomposition analysis, the springtime relationships between the mean sea-level pressure field over the North Atlantic and the regional wind gusts over the Iberian Peninsula, identifying the main atmospheric circulation patterns linked to gust wind speed anomaly configurations. The statistical significance of the obtained modes is investigated by means of Monte Carlo approach. The analysis highlighted that the covariability is dominated by two main large-scale features of the atmospheric circulation over the North Atlantic. The first mode relates to Iberian gust wind speeds to the Scandinavian pattern (SCAND), linking the large-scale pattern to above-normal wind gusts. The second covariability mode, associated with the North Atlantic Oscillation (NAO) pattern, correlates with maximum wind speeds over Iberia. An enhanced spring NAO pattern is related to positive (negative) wind gust correlations over northern (southern) Iberia. To find true relationships between large-scale atmospheric field and the gust wind speeds, composite maps were built up to give an average atmospheric circulation associated with coherent wind gust variability over Iberia.

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