scholarly journals Asymmetry of Daily Temperature Records

2008 ◽  
Vol 65 (10) ◽  
pp. 3327-3336 ◽  
Author(s):  
Yosef Ashkenazy ◽  
Yizhak Feliks ◽  
Hezi Gildor ◽  
Eli Tziperman
Keyword(s):  
Daily Temperature ◽  
High Latitudes ◽  
Atmospheric Conditions ◽  
Cyclone Activity ◽  
Radiative Relaxation ◽  
Cold Air ◽  
Cold Fronts ◽  
Mean Temperature ◽  
Temperature Records

The authors study the NCEP–NCAR reanalysis temperature records and find that surface daily mean temperature cools rapidly and warms gradually at the midlatitudes (around 40°N and 40°S). This “asymmetry” is partially related to the midlatitude cyclone activity, in which cold fronts are significantly faster and steeper than warm fronts, and to intrusions of cold air. The gradual warming may be attributed also to the radiative relaxation to average atmospheric conditions after the passage of cold fronts or other intrusions of cold air. At the high latitudes there is an opposite asymmetry with rapid warming and gradual cooling; this asymmetry may be attributed to the radiative relaxation to average cold atmospheric conditions after the passage of warm fronts or intrusions of warm air.

scholarly journals Nonlinear correlations of daily temperature records over land

2006 ◽  
Vol 13 (5) ◽  
pp. 571-576 ◽  
Author(s):  
I. Bartos ◽  
I. M. Jánosi
Keyword(s):  
Daily Temperature ◽  
Fluctuation Analysis ◽  
Temperature Changes ◽  
Temporal Correlations ◽  
Temperature Records ◽  
Global Statistics ◽  
Correlation Properties ◽  
Nonlinear Correlations ◽  
Detrended Fluctuation ◽  
Temperature Time

Abstract. We present a near global statistics on the correlation properties of daily temperature records. Data from terrestrial meteorological stations in the Global Daily Climatology Network are analyzed by means of detrended fluctuation analysis. Long-range temporal correlations extending up to several years are detected for each station. In order to reveal nonlinearity, we evaluated the magnitude of daily temperature changes (volatility) by the same method. The results clearly indicate the presence of nonlinearities in temperature time series, furthemore the geographic distribution of correlation exponents exhibits well defined clustering.

Subarea characteristics of the long-range correlations and the index χ for daily temperature records over China

2012 ◽  
Vol 109 (1-2) ◽  
pp. 261-270 ◽  
Author(s):  
Lei Jiang ◽  
Naiming Yuan ◽  
Zuntao Fu ◽  
Dongxiao Wang ◽  
Xia Zhao ◽  
...  
Keyword(s):  
Long Range ◽  
Daily Temperature ◽  
Long Range Correlations ◽  
Temperature Records

scholarly journals Footprint of greenhouse forcing in daily temperature variability

2021 ◽  
Vol 118 (32) ◽  
pp. e2103294118
Author(s):  
Maximilian Kotz ◽  
Leonie Wenz ◽  
Anders Levermann
Keyword(s):  
High Frequency ◽  
Climate Models ◽  
Coupled Model ◽  
Climatic Conditions ◽  
Temperature Variability ◽  
Daily Temperature ◽  
Global Changes ◽  
High Latitudes ◽  
Protection Measures ◽  
Daily Variability

Changes in mean climatic conditions will affect natural and societal systems profoundly under continued anthropogenic global warming. Changes in the high-frequency variability of temperature exert additional pressures, yet the effect of greenhouse forcing thereon has not been fully assessed or identified in observational data. Here, we show that the intramonthly variability of daily surface temperature changes with distinct global patterns as greenhouse gas concentrations rise. In both reanalyses of historical observations and state-of-the-art projections, variability increases at low to mid latitudes and decreases at northern mid to high latitudes with enhanced greenhouse forcing. These latitudinally polarized daily variability changes are identified from internal climate variability using a recently developed signal-to-noise-maximizing pattern-filtering technique. Analysis of a multimodel ensemble from the Coupled Model Intercomparison Project Phase 6 shows that these changes are attributable to enhanced greenhouse forcing. By the end of the century under a business-as-usual emissions scenario, daily temperature variability would continue to increase by up to a further 100% at low latitudes and decrease by 40% at northern high latitudes. Alternative scenarios demonstrate that these changes would be limited by mitigation of greenhouse gases. Moreover, global changes in daily variability exhibit strong covariation with warming across climate models, suggesting that the equilibrium climate sensitivity will also play a role in determining the extent of future variability changes. This global response of the high-frequency climate system to enhanced greenhouse forcing is likely to have strong and unequal effects on societies, economies, and ecosystems if mitigation and protection measures are not taken.

scholarly journals Variability of the nighttime OH layer and mesospheric ozone at high latitudes during northern winter: influence of meteorology

2010 ◽  
Vol 10 (21) ◽  
pp. 10291-10303 ◽  
Author(s):  
A. Damiani ◽  
M. Storini ◽  
M. L. Santee ◽  
S. Wang
Keyword(s):  
Carbon Monoxide ◽  
Lower Thermosphere ◽  
Complete Disappearance ◽  
High Latitudes ◽  
Atmospheric Conditions ◽  
Short Term ◽  
Lower Altitude ◽  
Additional Tool ◽  
The Third ◽  
Short Term Variability

Abstract. Analyses of OH zonal means, recorded at boreal high latitudes by the Aura Microwave Limb Sounder (MLS) in winters of 2005–2009, have shown medium- (weeks) and short- (days) term variability of the nighttime OH layer. Because of the exceptional descent of air from the mesosphere-lower thermosphere (MLT) region, medium-term variability occurred during February 2006 and February/March 2009. The layer normally situated at about 82 km descended by about 5–7 km, and its density increased to more than twice January values. In these periods and location the abundance of the lowered OH layer is comparable to the OH values induced by Solar Energetic Particle (SEP) forcing (e.g., SEP events of January 2005) at the same altitudes. In both years, the descent of the OH layer was coupled with increased mesospheric temperatures, elevated carbon monoxide and an almost complete disappearance of ozone at the altitude of the descended layer (which was not observed in other years). Moreover, under these exceptional atmospheric conditions, the third ozone peak, normally at about 72 km, is shown to descend about 5 km to lower altitude and increase in magnitude, with maximum values recorded during February 2009. Short-term variability occurred during Sudden Stratospheric Warming (SSW) events, in particular in January 2006, February 2008 and January 2009, when dynamics led to a smaller abundance of the OH layer at its typical altitude. During these periods, there was an upward displacement of the OH layer coupled to changes in ozone and carbon monoxide. These perturbations were the strongest during the SSW of January 2009; coincident upper mesospheric temperatures were the lowest recorded over the late winters of 2005–2009. Finally, the series of SSW events that occurred in late January/February 2008 induced noticeable short-term variability in ozone at altitudes of both the ozone minimum and the third ozone peak. These phenomena, confined inside the polar vortex, are an additional tool that can be used to investigate mesospheric vortex dynamics.

Heavy Alpine snowfall in January 2019 connected to atmospheric blocking

2020 ◽  
Author(s):  
Kamilya Yessimbet ◽  
Andrea Steiner
Keyword(s):  
North Atlantic ◽  
Jet Stream ◽  
High Latitudes ◽  
Atmospheric Conditions ◽  
Atmospheric Blocking ◽  
Pressure System ◽  
Reanalysis Dataset ◽  
The North ◽  
Synoptic Conditions ◽  
The North Atlantic

<p>Winter weather and extreme events at mid-latitudes are determined by the atmospheric circulation variability, which is closely related to jet stream configuration and atmospheric blocking. In January 2019, record-breaking snowfall in the Northern Alps affected Austria and Germany. The event is linked to a typical weather regime of blocking over the North Atlantic and southward meridional moisture transport from the high latitudes to the Alps. This study investigates the synoptic conditions prior and during the event addressing possible forcing mechanisms for the extreme snowfall occurrence.</p><p>We analyzed the atmospheric conditions using the ERA-5 reanalysis dataset investigating geopotential height (GPH), pressure, temperature, and wind fields. For blocking detection, we applied a classical algorithm based on the reversal of mid-latitude 500 hPa GPH gradients. Evolution of surface conditions and snowfall impacts was studied based on the European daily high-resolution gridded dataset (E-OBS) and snow data provided by the Austrian weather service.</p><p>Tropospheric analysis revealed that a persistent blocking high over the North Atlantic played a major role in the meridional elongation of upper-level streams. A low-pressure system, embedded in the strongly meandering jet stream’s trough, modulated the moisture flow directly towards the Alpine mountains leading to record-breaking snowfall.</p><p>Prior to the event, a major sudden stratospheric warming (SSW) took place at Northern high latitudes. We discuss the initial atmospheric conditions including SSW, blocking, and impacts on surface weather in Europe, and particularly in the Alpine region.</p>

Trends in intra-seasonal temperature variability in Europe

2020 ◽  
Author(s):  
Tomas Krauskopf
Keyword(s):  
Western Europe ◽  
Climate Extremes ◽  
Individual Variability ◽  
Daily Temperature ◽  
Linear Regression Method ◽  
Seasonal Temperature ◽  
Mean Temperature ◽  
Daily Data ◽  
Change In Mean

<p>While long-term changes in measures of central tendency of climate elements, i. e. mean temperature, are well acknowledged, studies of trends in measures of their variability are much less common. This is despite the fact that trends in variability can have higher effect on climate extremes than trends in mean. Here, three measures of intra-seasonal variability are examined: 1) standard deviation of mean daily temperature 2) mean absolute value of day-to-day temperature change, 3) the range between the 90th and 10th quantile of mean daily temperature. ECA&D daily data from 180 stations and linear regression method are utilized to calculate trends of these characteristics in period from 1961 to 2012. Spatial distribution of trends in individual variability characteristics in Europe together with long-term change in mean and autocorrelation of mean temperature are demonstrated in maps. Significant trends (positive and negative) in all examined variability characteristics were found with substantial differences between seasons as well as between regions. On this basis, Europe is divided into 6 regions and trends are assessed in each reagion separately. While the most significant decrease in variability is observed in Northern Scandinavia and Iceland in winter, the most substantial increase is detected in Central and Western Europe in spring. Our results are accompanied by comparing the probability density function of daily temperature between periods 1961 – 1986 and 1987 – 2012 in each region showing how the shape of distribution of daily temperature has changed and if it could affect the changing number and value of temperature extremes.</p>

scholarly journals Front–orography interactions during landfall of the 1992 New Year's Day Storm

2020 ◽  
Vol 1 (1) ◽  
pp. 175-189 ◽  
Author(s):  
Clemens Spensberger ◽  
Sebastian Schemm
Keyword(s):  
West Coast ◽  
Wind Band ◽  
Sensitivity Analyses ◽  
Cold Air ◽  
Passive Advection ◽  
Cold Fronts ◽  
Warm Sector ◽  
The Way

Abstract. Although following a common synoptic evolution for this region, the 1992 New Year's Day Storm was associated with some of the strongest winds observed along the Norwegian west coast. The narrow wind band along its bent-back front became famous as the “poisonous tail” and paved the way towards today's sting jet terminology. This article re-examines the storm's landfall with a particular focus on the interaction with the orography. Sensitivity analyses based on WRF simulations demonstrate that the formation and the evolution of the warm-air seclusion and its poisonous tail are largely independent of orography. In contrast, the warm sector of the storm undergoes considerable orographically induced modifications. While moving over the orography, both warm and cold fronts are eroded rapidly. This development fits neither the cold-air-damming paradigm nor the passive-advection paradigm describing front–orography interactions. The warm sector is lifted over the orography, thereby accelerating the occlusion process. The insensitivity of the warm-air seclusion to the orographic modifications of the warm sector raises the question of to which extent these entities are still interacting after the onset of the occlusion process.

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