An Observational Analysis of the Zonal Wind Fields of Sharply Recurving, Slowly Recurving and Non-Recurving Cyclones

1991 ◽  
Author(s):  
Stephen J. Hodanish
2017 ◽  
Vol 34 (3) ◽  
pp. 657-667 ◽  
Author(s):  
Z. Sheng ◽  
J. W. Li ◽  
Y. Jiang ◽  
S. D. Zhou ◽  
W. L. Shi

AbstractStratospheric winds play a significant role in middle atmosphere dynamics, model research, and carrier rocket experiments. For the first time, 65 sets of rocket sounding experiments conducted at Jiuquan (41.1°N, 100.2°E), China, from 1967 to 2004 are presented to study horizontal wind fields in the stratosphere. At a fixed height, wind speed obeys the lognormal distribution. Seasonal mean winds are westerly in winter and easterly in summer. In spring and autumn, zonal wind directions change from the upper to the lower stratosphere. The monthly zonal mean winds have an annual cycle period with large amplitudes at high altitudes. The correlation coefficients for zonal winds between observations and the Horizontal Wind Model (HWM) with all datasets are 0.7. The MERRA reanalysis is in good agreement with rocketsonde data according to the zonal winds comparison with a coefficient of 0.98. The sudden stratospheric warming is an important contribution to biases in the HWM, because it changes the zonal wind direction in the midlatitudes. Both the model and the reanalysis show dramatic meridional wind differences with the observation data.


2005 ◽  
Vol 41 ◽  
pp. 121-130 ◽  
Author(s):  
Yuping Yan ◽  
Paul A. Mayewski ◽  
Shichang Kang ◽  
Eric Meyerson

AbstractUsing US National Centers for Environmental Prediction/US National Center for Atmospheric Research re-analysis data, we investigate the relationships between crustal ion (nssCa2+) concentrations from three West Antarctic ice cores, namely, Siple Dome (SD), ITASE00-1 (IT001) and ITASE01-5 (IT015), and primary components of the climate system, namely, air pressure/geopotential height, zonal (u) and meridional (v) wind strength. Linear correlation analyses between nssCa2+ concentrations and both air-pressure and wind fields for the period of overlap between records indicate that the SD nssCa2+ variation is positively correlated with spring circumpolar zonal wind, while IT001 nssCa2+ has a positive correlation with circumpolar zonal wind throughout the year (r > 0.3, p < 0.01). Intensified Southern Westerlies circulation is conducive to transport of more crustal aerosols to both sites. Further correlation analyses between nssCa2+ concentrations from SD and IT001 and atmospheric circulation suggest that the high inland plateau (represented by core IT001) is largely influenced by transport from the upper troposphere. IT015 nssCa2+ is negatively correlated with westerly wind in October and November, suggesting that stronger westerly circulation may weaken the transport of crustal species to IT015. Correlations of nssCa2+ from the three ice cores with the Antarctic Oscillation index are consistent with results developed from the wind-field investigation. In addition, calibration between nssCa2+ concentration and the multivariate El Niño–Southern Oscillation (ENSO) index shows that crustal species transport to IT001 is enhanced during strong ENSO events.


2021 ◽  
Author(s):  
Sigrid Böhm ◽  
David Salstein

&lt;p&gt;One special component of the Coupled Model Intercomparison Project phase 6 (CMIP6) is the so-called ScenarioMIP. Different Earth system variables are provided within this project originating from numerous models and model runs operated by research centers around the globe. The models simulate future climate, based on alternative scenarios of future greenhouse gas emissions and land use changes linked to socioeconomic factors. The simulations, which cover the 21&lt;sup&gt;st&lt;/sup&gt; century, use different forcings that are defined from a combination of possible future pathways of societal development, the Shared Socioeconomic Pathways (SSPs), and the Representative Concentration Pathways (RCPs), identified by what radiative forcing level might exist in 2100. In this study, we focus on the analysis of multi-model projections of zonal wind fields, stemming from historical simulations and from the four tier 1 alternate scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5. We investigate the integrated effect of variations in the atmosphere on the axial component of the Earth rotation vector, quantified as length of day (LOD) variations. Generally, larger emissions lead to some stronger zonal wind patterns in much of the upper atmosphere.&amp;#160; The long-term variability and trends in LOD are examined w.r.t. a multi-model-mean and compared with the respective variations in the projected global temperature to study the potential impact of global warming on the Earth rotation speed.&lt;/p&gt;


2004 ◽  
Vol 21 (12) ◽  
pp. 1840-1854 ◽  
Author(s):  
Katja Friedrich ◽  
Martin Hagen

Abstract By installing and linking additional receivers to a monostatic Doppler radar, several wind components can be measured and combined into a wind vector field. Such a bistatic Doppler radar network was developed in 1993 by the National Center for Atmospheric Research and has been in operation at different research departments. Since then, the accuracy of wind vectors has been investigated mainly based on theoretical examinations. Observational analysis of the accuracy has been limited to comparisons of dual-Doppler-derived wind vectors always including the monostatic Doppler radar. Intercomparisons to independent wind measurements have not yet been accomplished. In order to become an alternative to monostatic multiple–Doppler applications, the reliability of wind vector fields has to be also proven by observational analysis. In this paper wind vectors measured by a bistatic Doppler radar network are evaluated by 1) internally comparing results of bistatic receivers; 2) comparing with independent wind measurements observed by a second Doppler radar; and 3) comparing with in situ flight measurements achieved with a research aircraft during stratiform precipitation events. Investigations show how reliable bistatically measured wind fields are and how they can contribute highly to research studies, weather surveillance, and forecasting. As a result of the intercomparison, the instrumentation error of the bistatic receivers can be assumed to be within 1 m s−1. Differences between bistatic Doppler radar and independent measurements range mainly between 2 and 3 m s−1.


2016 ◽  
Vol 31 (7) ◽  
pp. 928-952 ◽  
Author(s):  
Emily C. Gill ◽  
Balaji Rajagopalan ◽  
Peter Molnar ◽  
Thomas M. Marchitto

2014 ◽  
Vol 71 (10) ◽  
pp. 3816-3836 ◽  
Author(s):  
Naoko Sakaeda ◽  
Paul E. Roundy

Abstract The mechanisms driving the upper-tropospheric zonal mean intraseasonal zonal wind associated with the Madden–Julian oscillation are examined through budget analysis during boreal winter. To diagnose the role of nonlinear and cross-scale interactions, the wind fields are decomposed into three temporal bands, including the intraseasonal time scale (30–100 days), and periods shorter and longer than the intraseasonal time scales. The intraseasonal zonal mean circulation and its driving mechanisms are first examined based on the leading EOFs of the intraseasonal zonal wind. Consistent with previous studies of intraseasonal atmospheric angular momentum, the upper-troposphere zonal mean intraseasonal zonal wind anomaly begins in the tropics and propagates poleward. Results show that interaction between the background state and intraseasonal-time-scale zonally symmetric and asymmetric circulation helps drive changes in the tropical intraseasonal zonal wind and its poleward propagation. The intraseasonal anomalous circulation also modulates the characteristics of the transient eddies that induce anomalous momentum flux convergence that then helps to accelerate further the intraseasonal zonal wind in the extratropics. Results also suggest that feedbacks between the anomalous intraseasonal circulation and transient eddies have some sensitivity to event-to-event variability of the MJO.


Author(s):  
Olga Mashtaler ◽  
Olga Mashtaler ◽  
Alexander Myasoedov ◽  
Alexander Myasoedov ◽  
Elizaveta Zabolotskikh ◽  
...  

The relevance of the polar lows (PLs) research is justified by their great destructive power and creation of threat to the safety of navigation in the high latitudes and along the Northern Sea Route. The most dangerous effects on maritime activities are strong winds, waves and icing. In addition, the study of the PLs acquires relevance due to the sharp decrease of the sea ice area in the Arctic in recent years and the emergence of areas of open water, suitable for the appearance and development of PLs. However, despite the importance of PLs, they are apparently not sufficiently studied. As there are no meteorological observations in the areas of their appearance, the main source of information about them are satellite observations. By using images on the SOLab SIOWS Arctic Portal from multiple satellites operating in the IR and visible ranges (e.g., MODIS and AVHRR), and using near-water wind fields from high resolution synthetic aperture radars (Sentine-1, ASAR) and low resolution scatterometers (ASCAT), we identify polar lows in various parts of the Arctic, revealing statistical regularities in the appearance of PLs, their distribution and intensity. Collected database of Pls and their characteristics will be used for further PLs forecasting model development.


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