scholarly journals The charmonium dissociation in an “anomalous wind”

2016 ◽  
Vol 2016 (1) ◽  
Author(s):  
Andrey V. Sadofyev ◽  
Yi Yin
Keyword(s):  
Anomalous Wind

scholarly journals Anomalous wind triggered the largest phytoplankton bloom in the oligotrophic North Pacific Subtropical Gyre

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chun Hoe Chow ◽  
Wee Cheah ◽  
Jen-Hua Tai ◽  
Sin-Fu Liu
Keyword(s):  
North Pacific ◽  
Phytoplankton Bloom ◽  
Subtropical Gyre ◽  
Velocity Shear ◽  
North Pacific Subtropical Gyre ◽  
The North ◽  
Large Eddy ◽  
Anomalous Wind ◽  
Anticyclonic Eddies

Abstract In summer 2010, a massive bloom appeared in the middle (16–25°N, 160–200°E) of the North Pacific Subtropical Gyre (NPSG) creating a spectacular oasis in the middle of the largest oceanic desert on Earth. Peaked in June 2010 covering over two million km2 in space, this phytoplankton bloom is the largest ever recorded by ocean color satellites in the NPSG over the period from 1997 to 2013. The initiation and mechanisms sustaining the massive bloom were due to atmospheric and oceanic anomalies. Over the north (25–30°N) of the bloom, strong anticyclonic winds warmed sea surface temperature (SST) via Ekman convergence. Subsequently, anomalous westward ocean currents were generated by SST meridional gradients between 19°N and 25°N, producing strong velocity shear that caused large number of mesoscale (100-km in order) cyclonic eddies in the bloom region. The ratio of cyclonic to anticyclonic eddies of 2.7 in summer 2010 is the highest over the 16-year study period. As a result of the large eddy-number differences, eddy-eddy interactions were strong and induced submesoscale (smaller than 100 km) vertical pumping as observed in the in-situ ocean profiles. The signature of vertical pumping was also presented in the in-situ measurements of chlorophyll and nutrients, which show higher concentrations in 2010 than other years.

A pilot study on the interactions between katabatic winds and polynyas at the Adélie Coast, eastern Antarctica

1995 ◽  
Vol 7 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Ute Adolphs ◽  
Gerd Wendler
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Katabatic Wind ◽  
Data Sets ◽  
Strong Wind ◽  
Coastal Sea ◽  
Coastal Winds ◽  
Temperature Contrast ◽  
Wind Events ◽  
Anomalous Wind

Infrared satellite images of the coastal area off Adélie Land were examined together with two wind data sets, one from the manned French station, Dumont d'Urville, the other one from an Automatic Weather Station (AWS) during the 1986 austral winter. A correlation between the development of open water areas (polynyas) and the appearance of extremely strong offshore winds can be drawn. The wind direction tended to be more perpendicular to the coastline during these extreme ‘events’, suggesting a katabatic origin of the increase in wind strength. In the study area the influence of the katabatic wind on the sea ice extends 20–100 km offshore. Sea ice motion further off the coast seems to be more dominated by synoptic scale weather systems. Broader scale atmospheric influences may create large polynya structures which influence the development of coastal winds, as the temperature contrast between open water and the cold continent generates its own circulation. Strong wind events can have a weakening effect on the coastal sea ice which can lead to a much more sensitive reaction of the sea ice in response to following anomalous wind events.

scholarly journals A Surface Wind Extremes (“Wind Lulls” and “Wind Blows”) Climatology for Central North America and Adjoining Oceans (1979–2012)

2015 ◽  
Vol 54 (3) ◽  
pp. 643-657 ◽  
Author(s):  
Jonny W. Malloy ◽  
Daniel S. Krahenbuhl ◽  
Chad E. Bush ◽  
Robert C. Balling ◽  
Michael M. Santoro ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
North Atlantic Ocean ◽  
Grid Point ◽  
Surface Wind ◽  
Wind Speeds ◽  
The North ◽  
Anomalous Wind

AbstractThis study explores long-term deviations from wind averages, specifically near the surface across central North America and adjoining oceans (25°–50°N, 60°–130°W) for 1979–2012 (408 months) by utilizing the North American Regional Reanalysis 10-m wind climate datasets. Regions where periods of anomalous wind speeds were observed (i.e., 1 standard deviation below/above both the long-term mean annual and mean monthly wind speeds at each grid point) were identified. These two climatic extremes were classified as wind lulls (WLs; below) or wind blows (WBs; above). Major findings for the North American study domain indicate that 1) mean annual wind speeds range from 1–3 m s−1 (Intermountain West) to over 7 m s−1 (offshore the East and West Coasts), 2) mean durations for WLs and WBs are high for much of the southeastern United States and for the open waters of the North Atlantic Ocean, respectively, 3) the longest WL/WB episodes for the majority of locations have historically not exceeded 5 months, 4) WLs and WBs are most common during June and October, respectively, for the upper Midwest, 5) WLs are least frequent over the southwestern United States during the North American monsoon, and 6) no significant anomalous wind trends exist over land or sea.

scholarly journals How Momentum Coupling Affects SST Variance and Large-Scale Pacific Climate Variability in CESM

2018 ◽  
Vol 31 (7) ◽  
pp. 2927-2944 ◽  
Author(s):  
Sarah M. Larson ◽  
Daniel J. Vimont ◽  
Amy C. Clement ◽  
Ben P. Kirtman
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Ocean Dynamics ◽  
Easterly Wind ◽  
Tropical Forcing ◽  
Freshwater Fluxes ◽  
The Pacific ◽  
Anomalous Wind ◽  
Momentum Coupling ◽  
The Impact

The contribution of buoyancy (thermal + freshwater fluxes) versus momentum (wind driven) coupling to SST variance in climate models is a longstanding question. Addressing this question has proven difficult because a gap in the model hierarchy exists between the fully coupled (momentum + buoyancy + ocean dynamics) and slab–mixed layer ocean coupled (thermal with no ocean dynamics) versions. The missing piece is a thermally coupled configuration that permits anomalous ocean heat transport convergence decoupled from the anomalous wind stress. A mechanically decoupled model configuration is provided to fill this gap and diagnose the impact of momentum coupling on SST variance in NCAR CESM. A major finding is that subtropical SST variance increases when momentum coupling is disengaged. An “opposing flux hypothesis” may explain why the subtropics (midlatitudes) experience increased (reduced) variance without momentum coupling. In a subtropical easterly wind regime, Ekman fluxes [Formula: see text] oppose thermal fluxes [Formula: see text], such that when the air and sea are mechanically decoupled [Formula: see text], [Formula: see text] variance increases. As a result, SST variance increases. In a midlatitude westerly regime where [Formula: see text] and [Formula: see text] typically reinforce each other, SST variance is reduced. Changes in mean surface winds with climate change could impact the [Formula: see text] and [Formula: see text] covariance relationships. A by-product of mechanically decoupling the model is the absence of ENSO variability. The Pacific decadal oscillation operates without momentum coupling or tropical forcing, although the pattern is modified with enhanced (reduced) variability in the subtropics (midlatitudes). Results show that Ekman fluxes are an important component to tropical, subtropical, and midlatitude SST variance.

scholarly journals Gravity-wave momentum fluxes in the mesosphere over Ascension Island (8° S, 14° W) and the anomalous zonal winds of the semi-annual oscillation in 2002

2016 ◽  
Vol 34 (2) ◽  
pp. 323-330 ◽  
Author(s):  
Andrew C. Moss ◽  
Corwin J. Wright ◽  
Robin N. Davis ◽  
Nicholas J. Mitchell
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
High Frequency ◽  
Wave Forcing ◽  
Zonal Winds ◽  
Ascension Island ◽  
Wind Event ◽  
Momentum Fluxes ◽  
Anomalous Wind ◽  
Wave Induced

Abstract. Anomalously strong westward winds during the first phase of the equatorial mesospheric semi-annual oscillation (MSAO) have been attributed to unusual filtering conditions producing exceptional gravity-wave fluxes. We test this hypothesis using meteor-radar measurements made over Ascension Island (8° S, 14° W). An anomalous wind event in 2002 of −85.5 ms−1 occurred simultaneously with the momentum fluxes of high-frequency gravity waves reaching the largest observed westward values of −29 m2 s−2 and strong westward wind accelerations of −510 ms−1 day−1. However, despite this strong wave forcing during the event, no unusual filtering conditions or significant increases in wave-excitation proxies were observed. Further, although strong westward wave-induced accelerations were also observed during the 2006 MSAO first phase, there was no corresponding simultaneous response in westward wind. We thus suggest that strong westward fluxes/accelerations of high-frequency gravity waves are not always sufficient to produce anomalous first-phase westward MSAO winds and other forcing may be significant.

scholarly journals Moist Dynamical Linkage between the Equatorial Indian Ocean and the South Asian Monsoon Trough*

2010 ◽  
Vol 67 (3) ◽  
pp. 589-610 ◽  
Author(s):  
H. Annamalai
Keyword(s):  
Indian Ocean ◽  
Moisture Content ◽  
Equatorial Indian Ocean ◽  
Monsoon Trough ◽  
Boreal Summer ◽  
Coupled Models ◽  
Precipitation Anomalies ◽  
Anomalous Wind ◽  
Normal Rainfall ◽  
Sst Anomalies

Abstract During boreal summer, both the monsoon trough and the equatorial Indian Ocean (EIO) receive intense climatological precipitation. At various time scales, EIO sea surface temperature (SST) and/or precipitation variations interact with rainfall along the trough. For instance, during July–August in strong Indian Ocean dipole/zonal mode (IODZM) years, EIO experiences below-normal rainfall while regions along the monsoon trough receive above-normal rainfall. A lack of spatial coherency between SST and precipitation variations is noted in both regions. This paper posits the hypothesis that interaction between equatorial waves and moist physics is important in determining precipitation anomalies over these regions and in setting up the teleconnection. The hypothesis is tested using a linear baroclinic model (LBM). IODZM-related SST anomalies derived from multicentury integrations of the Geophysical Fluid Dynamics Laboratory coupled model (GFDL CM2.1) are used to force the LBM. Consistent with observations and CM2.1 composites of strong IODZM events, steady-state LBM solutions simulate zonally oriented negative (positive) precipitation anomalies over the EIO (along the monsoon trough). To identify the processes simulated in the LBM, moisture and moist static energy budgets are examined. Over both regions, analyses reveal that moisture advection contributes the most to the LBM budget, with advection of climatological moisture by the anomalous wind being the principal factor. Specifically, in response to cold SST anomalies in the EIO, moist stability due to surface fluxes increases, giving rise to below-normal rainfall. These conditions produce anomalous anticyclonic circulation as a Rossby wave response in the lower troposphere. Over the central-eastern EIO, this anomalous circulation advects climatological air of lower moisture content from the subtropics. In addition, advection of anomalous moisture by both climatological and anomalous wind results in anomalous dry conditions over the entire EIO. In contrast, anomalous divergent circulations that emanate from the EIO advect climatological air of higher moisture content from the equatorial region, amplifying rainfall along the monsoon trough. Consequently, the two regions are connected by a thermally driven overturning meridional circulation. Budget diagnostics performed with CM2.1 composites and the ECMWF interim reanalysis for observed IODZM events support the hypothesis. The results here imply that in coupled models, realistic representation of the basic state and details of the moist processes are necessary for successful monsoon prediction.

scholarly journals Dynamical Mechanism for the Increase in Tropical Upwelling in the Lowermost Tropical Stratosphere during Warm ENSO Events

2010 ◽  
Vol 67 (7) ◽  
pp. 2331-2340 ◽  
Author(s):  
N. Calvo ◽  
R. R. Garcia ◽  
W. J. Randel ◽  
D. R. Marsh
Keyword(s):  
Gravity Waves ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Southern Oscillation ◽  
Dynamical Mechanism ◽  
Wind Pattern ◽  
Upper Troposphere ◽  
Enso Events ◽  
Anomalous Wind ◽  
Recent Version

Abstract The Brewer–Dobson circulation strengthens in the lowermost tropical stratosphere during warm El Niño–Southern Oscillation (ENSO) events. Dynamical analyses using the most recent version of the Whole Atmosphere Community Climate Model show that this is due mainly to anomalous forcing by orographic gravity waves, which maximizes in the Northern Hemisphere subtropics between 18 and 22 km, especially during the strongest warm ENSO episodes. Anomalies in the meridional gradient of temperature in the upper troposphere and lower stratosphere (UTLS) are produced during warm ENSO events, accompanied by anomalies in the location and intensity of the subtropical jets. This anomalous wind pattern alters the propagation and dissipation of the parameterized gravity waves, which ultimately force increases in tropical upwelling in the lowermost stratosphere. During cold ENSO events a similar signal, but of opposite sign, is present in the model simulations. The signals in ozone and water vapor produced by ENSO events in the UTLS are also investigated.

Variability and Predictability of a Three-Dimensional Hurricane in Statistical Equilibrium

2013 ◽  
Vol 70 (6) ◽  
pp. 1806-1820 ◽  
Author(s):  
Bonnie R. Brown ◽  
Gregory J. Hakim
Keyword(s):  
Inverse Modeling ◽  
Environmental Variability ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Internal Variability ◽  
Maximum Wind ◽  
Tangential Wind ◽  
Cloud Resolving Model ◽  
Anomalous Wind

Abstract The internal variability and predictability of idealized three-dimensional hurricanes is investigated using 100-day-long, statistically steady simulations in a compressible, nonhydrostatic, cloud-resolving model. The equilibrium solution is free of the confounding effects of initial conditions and environmental variability in order to isolate the “intrinsic” characteristics of the hurricane. The variance of the axisymmetric tangential velocity is dominated by two patterns: one characterized by a radial shift of the maximum wind, and the other by intensity modulation at the radius of maximum wind. These patterns are associated with convectively coupled bands of anomalous wind speed that propagate inward from large radii with a period of roughly 5 days, the strongest of which is associated with an eyewall replacement cycle. The asymmetric tangential wind is strongest radially inward of the radius of maximum wind. On average, asymmetries decelerate the azimuthal-mean tangential wind at the radius of maximum wind and accelerate it along the inner edge of eyewall. Predictability of axisymmetric storm structure is measured through the autocorrelation e-folding time and linear inverse modeling. Results from both methods reveal an intrinsic predictability time scale of about 2 days. The predictability and variability of the axisymmetric storm structure are consistent with recently obtained results from idealized axisymmetric hurricane modeling.

scholarly journals Interpreting Observed Temperature Probability Distributions Using a Relationship between Temperature and Temperature Advection

2021 ◽  
pp. 1-53
Author(s):  
Marianna Linz ◽  
Gang Chen
Keyword(s):  
Probability Distributions ◽  
Equilibrium Temperature ◽  
Land Area ◽  
Simple Method ◽  
Conditional Mean ◽  
Temperature Distributions ◽  
Temperature Advection ◽  
Cold Events ◽  
Anomalous Wind ◽  
Spatially Variant

Abstract The non-normality of temperature probability distributions and the physics that drive it are important due to their relationships to the frequency of extreme warm and cold events. Here we use a conditional mean framework to explore how horizontal temperature advection and other physical processes work together to control the shape of daily temperature distributions during 1979-2019 in the ERA5 reanalysis for both JJA and DJF. We demonstrate that the temperature distribution in mid- and high- latitudes can largely be linearly explained by the conditional mean horizontal temperature advection with the simple treatment of other processes as a Newtonian relaxation with a spatially-variant relaxation time scale and equilibrium temperature. We analyze the role of different transient and stationary components of the horizontal temperature advection in affecting the shape of temperature distributions. The anomalous advection of the stationary temperature gradient has a dominant effect in influencing temperature variance, while both that term and the covariance between anomalous wind and anomalous temperature have significant effects on temperature skewness. While this simple method works well over most of the ocean, the advection-temperature relationship is more complicated over land. We classify land regions with different advection-temperature relationships under our framework, and find that for both seasons the aforementioned linear relationship can explain ~30% of land area, and can explain either the lower or the upper half of temperature distributions in an additional ~30% of land area. Identifying the regions where temperature advection explains shapes of temperature distributions well will help us gain more confidence in understanding the future change of temperature distributions and extreme events.

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