scholarly journals Occurrence, Variability and Trends in Snowfall and Rainfall under the background of air temperature and Atmospheric Circulation in Poland

2021 ◽  
Author(s):  
Ewa Łupikasza ◽  
Łukasz Małarzewski
Keyword(s):  
Atmospheric Circulation ◽  
Air Temperature ◽  
Negative Correlation ◽  
Freezing Point ◽  
Teleconnection Patterns ◽  
Solid Precipitation ◽  
Recent Climate ◽  
Wide Range ◽  
Liquid Precipitation ◽  
Precipitation Phase

<p>The reaction of precipitation on current warming is ambiguous and differs depending on the region. Particular precipitation phases were found to respond more significantly to recent climate change in many areas located in North America, Asia, Europe and mountains. Since precipitation is an important factor in many environmental processes, trends in its occurrence and totals may trigger various changes in the Earth system and affect life.</p><p>This study aims to recognize the influence of air temperature and atmospheric circulation on the occurrence, variability and trends in precipitation phase indices. We used sub-daily data (every 3h) on air temperature, precipitation totals, notation of weather phenomena in the form of a current (ww) and past weather (W1W2) and cloud types from 38 synoptic stations located in Poland. Moreover, we used various teleconnection patterns to describe macroscale circulation and circulation types to describe regional circulation. Unlike in most studies, precipitation phase was identified based on notation of weather phenomena. Such an approach allowed us to assess a real range of surface air temperature (2m above ground) where snowfall and rainfall occur. Both frequency, totals and quotient of particular precipitation phases were analysed over the period of 1966-2020.  </p><p>Our preliminary results showed that each precipitation phase occurred over a wide range of temperatures; however, most snowfall registered during air temperatures far above freezing point (even 6°C) fell during the existence of cumulonimbus, which indicates strong convection. The highest probability of solid precipitation was linked to air advection from the north-eastern sector under the influence of cyclone (ca.15-20%). Mixed precipitation could be most expected during days with a cyclone centre located over Poland (ca. 20%). The highest probability of liquid precipitation (ca. 70%) was most characteristic of the west and north-west advection under the influence of cyclone and during the cyclone centre or trough over Poland.  </p><p>High year-to-year variability in the indices of precipitation phases impacted their trends. However, liquid precipitation tended to increase in winter over most of the stations. Mixed precipitation exhibited various trend directions depending on the region in winter and decreasing spring and autumn trends. In transitional seasons, a significant decrease was also found in solid precipitation. Most of these changes were significantly related to changes in air temperature except for solid precipitation in winter. Variability in precipitation phases was also correlated with teleconnection patterns, including NAO (negative correlation with solid precipitation in spring and autumn and liquid precipitation in summer, positive correlation with mixed pre in winter), EA (negative correlation with mixed precipitation in autumn) and SCAND (negative correlation with mixed precipitation in winter).</p><p> </p><p>The research performed within the project No. 2017/27/B/ST10/00923, financed by National Science Centre,</p>

scholarly journals Long-term changes in precipitation phase in Czechia

Geografie ◽  
2019 ◽  
Vol 124 (1) ◽  
pp. 41-55
Author(s):  
Martin Hynčica ◽  
Radan Huth
Keyword(s):  
Air Temperature ◽  
Daily Precipitation ◽  
Sharp Decrease ◽  
Total Precipitation ◽  
Solid Precipitation ◽  
The Past ◽  
Air Temperatures ◽  
Long Term Changes ◽  
Precipitation Phase

Long-term changes in precipitation phase are investigated at ten stations in Czechia. Trends are calculated from 1983 to 2018 for the period between November and April. Daily SYNOP reports and daily precipitation totals are used at every station, where number and occurrence of specific codes in SYNOP report determine daily precipitation totals as solid, combined (which represents, to a large extent, category of mixed precipitation), or liquid. Thereafter, it is possible to calculate trends of all precipitation phases as well as the proportion of solid to total precipitation (S/P; in %). The average S/P trend over all Czech stations is significantly negative (−0.60%·year-1) and accompanied by a sharp decrease in solid precipitation (−1.66 mm·year-1) and an increase in combined precipitation (1.50 mm·year-1). Thus, our results show a ship of precipitation phase from solid to combined. Because of the dependence of S/P on air temperature, we suppose that the current S/P decline is a manifestation of rising air temperatures in the past decades.

scholarly journals Long-Term Variability of Precipitation form in Hornsund (Spitsbergen) in Relation to Atmospheric Circulation (1979–2009)

2010 ◽  
Vol 3 (1) ◽  
pp. 65-86 ◽  
Author(s):  
Ewa Łupikasza
Keyword(s):  
Atmospheric Circulation ◽  
Arctic Oscillation ◽  
The Other ◽  
Solid Precipitation ◽  
Precipitation Characteristics ◽  
Minor Influence ◽  
A Minor ◽  
The Impact ◽  
Liquid Precipitation

Abstract The paper discusses the impact of the atmospheric circulation on the long-term variability of liquid, mixed and solid precipitation. The three precipitation forms were characterised by their totals, the number of days when they prevailed, and the contribution of each to the overall precipitation totals. Trends, as a background to further analysis, were calculated with regard to each characteristic of each precipitation form. The most significant increases were recorded in the contribution of liquid precipitation to the overall precipitation totals in September and in the mixed precipitation totals in December and November. Arctic Oscillation (AO) was found to have only a minor influence on the long-term variability of precipitation characteristics. The AO phase could to some degree account for the observed variation in the number of days with liquid precipitation. On the other hand, the direction of the local advection could account for considerably more of this variability and also the variability in liquid precipitation totals.

scholarly journals On the Role of Tropospheric Circulation in Recent Climate Changes in the Antarctic Peninsula Region

2009 ◽  
Vol 1 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Vladislav E. Tymofeyev
Keyword(s):  
Atmospheric Circulation ◽  
Air Temperature ◽  
Antarctic Peninsula ◽  
Winter Season ◽  
Recent Decade ◽  
Second Phase ◽  
Regional Warming ◽  
Recent Climate ◽  
Tropospheric Circulation ◽  
The Antarctic

Abstract The state of tropospheric circulation in the West Antarctic sector (WAS) is considered during 1990s, the warmest decade in the Antarctic Peninsula (AP) region. Regional warming has progressed almost coherently with the second phase of global warming and is related to oceanic variability, specifically PDO-ENSO conditions. Atmospheric circulation in 1990s comprises a prevailing cyclogenesis west of the Antarctic Peninsula sector along with frequent weather modifications (the winter season in particular is examined) and the ridge of high pressure to the east. Predominant atmospheric circulation types for the recent decade are found to be stable in time causing smaller air temperature oscillations on different time scales. The circulation background responsible for the stabilization of air temperature growth in the AP region immediately after the turn of the millennium is shown.

scholarly journals A Parameterization of the Probability of Snow–Rain Transition

2015 ◽  
Vol 16 (4) ◽  
pp. 1466-1477 ◽  
Author(s):  
Elizabeth M. Sims ◽  
Guosheng Liu
Keyword(s):  
Land Cover ◽  
Air Temperature ◽  
Surface Pressure ◽  
Lapse Rate ◽  
Land Cover Type ◽  
Vertical Temperature ◽  
Near Surface ◽  
Temperature Lapse Rate ◽  
Solid Precipitation ◽  
Precipitation Phase

Abstract When estimating precipitation using remotely sensed observations, it is important to correctly classify the phase of precipitation. A misclassification can result in order-of-magnitude errors in the estimated precipitation rate. Using global ground-based observations over multiple years, the influence of different geophysical parameters on precipitation phase is investigated, with the goal of obtaining an improved method for determining precipitation phase. The parameters studied are near-surface air temperature, atmospheric moisture, low-level vertical temperature lapse rate, surface skin temperature, surface pressure, and land cover type. To combine the effects of temperature and moisture, wet-bulb temperature, instead of air temperature, is used as a key parameter for separating solid and liquid precipitation. Results show that in addition to wet-bulb temperature, vertical temperature lapse rate affects the precipitation phase. For example, at a near-surface wet-bulb temperature of 0°C, a lapse rate of 6°C km−1 results in an 86% conditional probability of solid precipitation, while a lapse rate of −2°C km−1 results in a 45% probability. For near-surface wet-bulb temperatures less than 0°C, skin temperature affects precipitation phase, although the effect appears to be minor. Results also show that surface pressure appears to influence precipitation phase in some cases; however, this dependence is not clear on a global scale. Land cover type does not appear to affect precipitation phase. Based on these findings, a parameterization scheme has been developed that accepts available meteorological data as input and returns the conditional probability of solid precipitation.

Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame

2020 ◽  
Vol 1008 ◽  
pp. 128-138
Author(s):  
Ahmed M. Salman ◽  
Ibrahim A. Ibrahim ◽  
Hamada M. Gad ◽  
Tharwat M. Farag
Keyword(s):  
Air Temperature ◽  
Diffusion Flame ◽  
Nitrogen Addition ◽  
Flame Length ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Air Temperatures ◽  
Air Stream ◽  
Wide Range

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

scholarly journals Performance of the Precipitation Occurrence Sensor System as a Precipitation Gauge

2008 ◽  
Vol 25 (2) ◽  
pp. 196-212 ◽  
Author(s):  
B. E. Sheppard ◽  
P. I. Joe
Keyword(s):  
Interquartile Range ◽  
Sensor System ◽  
Precipitation Rate ◽  
Doppler Velocity ◽  
High Temporal Resolution ◽  
Velocity Spectrum ◽  
Ratio Distribution ◽  
Precipitation Occurrence ◽  
Solid Precipitation ◽  
Wide Range

Abstract The Precipitation Occurrence Sensor System (POSS) is a small X-band Doppler radar originally developed by the Meteorological Service of Canada for reporting the occurrence, type, and intensity of precipitation from Automated Weather Observing Stations. This study evaluates POSS as a gauge for measuring amounts of both liquid and solid precipitation. Different precipitation rate estimation algorithms are described. The effect of different solid precipitation types on the Doppler velocity spectrum is discussed. Lacking any accepted reference for high temporal resolution rates, the POSS precipitation rate measurements are integrated over time periods ranging from 6 h to one day and validated against international and Canadian reference gauges. Data from a wide range of sites across Canada and for periods of several years are used. The statistical performance of POSS is described in terms of the distribution of ratios of POSS to reference gauge amounts (catch ratios). In liquid precipitation the median of the catch ratio distribution is 82% and the interquartile range was between −12% and 19% about the median. In solid precipitation the median is 90% and the interquartile range is between −17% and 24% about the median. The underestimation in both liquid and solid precipitation is shown to be a function of precipitation rate and phase. The effects of radome wetting, raindrop splashing, wind, and the radar “brightband” effect on the estimation of precipitation rates are discussed.

scholarly journals Trends and regime shifts in climatic conditions and river runoff in Estonia during 1951–2015

2017 ◽  
Vol 8 (4) ◽  
pp. 963-976 ◽  
Author(s):  
Jaak Jaagus ◽  
Mait Sepp ◽  
Toomas Tamm ◽  
Arvo Järvet ◽  
Kiira Mõisja
Keyword(s):  
Time Series ◽  
Snow Cover ◽  
Atmospheric Circulation ◽  
Air Temperature ◽  
Large Scale ◽  
Regime Shifts ◽  
The Arctic ◽  
Dry Period ◽  
Snow Cover Duration ◽  
Large Scale Atmospheric Circulation

Abstract. Time series of monthly, seasonal and annual mean air temperature, precipitation, snow cover duration and specific runoff of rivers in Estonia are analysed for detecting of trends and regime shifts during 1951–2015. Trend analysis is realised using the Mann–Kendall test and regime shifts are detected with the Rodionov test (sequential t-test analysis of regime shifts). The results from Estonia are related to trends and regime shifts in time series of indices of large-scale atmospheric circulation. Annual mean air temperature has significantly increased at all 12 stations by 0.3–0.4 K decade−1. The warming trend was detected in all seasons but with the higher magnitude in spring and winter. Snow cover duration has decreased in Estonia by 3–4 days decade−1. Changes in precipitation are not clear and uniform due to their very high spatial and temporal variability. The most significant increase in precipitation was observed during the cold half-year, from November to March and also in June. A time series of specific runoff measured at 21 stations had significant seasonal changes during the study period. Winter values have increased by 0.4–0.9 L s−1 km−2 decade−1, while stronger changes are typical for western Estonia and weaker changes for eastern Estonia. At the same time, specific runoff in April and May have notably decreased indicating the shift of the runoff maximum to the earlier time, i.e. from April to March. Air temperature, precipitation, snow cover duration and specific runoff of rivers are highly correlated in winter determined by the large-scale atmospheric circulation. Correlation coefficients between the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) indices reflecting the intensity of westerlies, and the studied variables were 0.5–0.8. The main result of the analysis of regime shifts was the detection of coherent shifts for air temperature, snow cover duration and specific runoff in the late 1980s, mostly since the winter of 1988/1989, which are, in turn, synchronous with the shifts in winter circulation. For example, runoff abruptly increased in January, February and March but decreased in April. Regime shifts in annual specific runoff correspond to the alternation of wet and dry periods. A dry period started in 1964 or 1963, a wet period in 1978 and the next dry period at the beginning of the 21st century.

scholarly journals The faint young Sun problem revisited with a 3-D climate–carbon model – Part 1

2014 ◽  
Vol 10 (2) ◽  
pp. 697-713 ◽  
Author(s):  
G. Le Hir ◽  
Y. Teitler ◽  
F. Fluteau ◽  
Y. Donnadieu ◽  
P. Philippot
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Freezing Point ◽  
Climatic Factors ◽  
General Circulation Models ◽  
Companion Paper ◽  
One Dimensional ◽  
Carbon Dioxide Concentrations ◽  
Wide Range ◽  
High Concentrations

Abstract. During the Archaean, the Sun's luminosity was 18 to 25% lower than the present day. One-dimensional radiative convective models (RCM) generally infer that high concentrations of greenhouse gases (CO2, CH4) are required to prevent the early Earth's surface temperature from dropping below the freezing point of liquid water and satisfying the faint young Sun paradox (FYSP, an Earth temperature at least as warm as today). Using a one-dimensional (1-D) model, it was proposed in 2010 that the association of a reduced albedo and less reflective clouds may have been responsible for the maintenance of a warm climate during the Archaean without requiring high concentrations of atmospheric CO2 (pCO2). More recently, 3-D climate simulations have been performed using atmospheric general circulation models (AGCM) and Earth system models of intermediate complexity (EMIC). These studies were able to solve the FYSP through a large range of carbon dioxide concentrations, from 0.6 bar with an EMIC to several millibars with AGCMs. To better understand this wide range in pCO2, we investigated the early Earth climate using an atmospheric GCM coupled to a slab ocean. Our simulations include the ice-albedo feedback and specific Archaean climatic factors such as a faster Earth rotation rate, high atmospheric concentrations of CO2 and/or CH4, a reduced continental surface, a saltier ocean, and different cloudiness. We estimated full glaciation thresholds for the early Archaean and quantified positive radiative forcing required to solve the FYSP. We also demonstrated why RCM and EMIC tend to overestimate greenhouse gas concentrations required to avoid full glaciations or solve the FYSP. Carbon cycle–climate interplays and conditions for sustaining pCO2 will be discussed in a companion paper.

scholarly journals Relationships of surface air temperature anomalies over Europe to persistence of atmospheric circulation patterns conducive to heat waves

2008 ◽  
Vol 14 ◽  
pp. 243-249 ◽  
Author(s):  
J. Kyselý ◽  
R. Huth
Keyword(s):  
Atmospheric Circulation ◽  
Air Temperature ◽  
Heat Waves ◽  
Temperature Extremes ◽  
Human Society ◽  
Positive Temperature ◽  
Temperature Anomalies ◽  
Circulation Types ◽  
Circulation Patterns ◽  
Air Temperature Anomalies

Abstract. Heat waves are among natural hazards with the most severe consequences for human society, including pronounced mortality impacts in mid-latitudes. Recent studies have hypothesized that the enhanced persistence of atmospheric circulation may affect surface climatic extremes, mainly the frequency and severity of heat waves. In this paper we examine relationships between the persistence of the Hess-Brezowsky circulation types conducive to summer heat waves and air temperature anomalies at stations over most of the European continent. We also evaluate differences between temperature anomalies during late and early stages of warm circulation types in all seasons. Results show that more persistent circulation patterns tend to enhance the severity of heat waves and support more pronounced temperature anomalies. Recent sharply rising trends in positive temperature extremes over Europe may be related to the greater persistence of the circulation types, and if similar changes towards enhanced persistence affect other mid-latitudinal regions, analogous consequences and implications for temperature extremes may be expected.

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