Natural Environment of Poland: Climate

Main Factors of Polish Climate

• Geographical and Atmospheric Drivers: The climate of Poland is shaped by its position in the middle latitudes and within the temperate climate zone.
• Marine Influences: The North Atlantic Current significantly impacts the region.
• Circulation Patterns: Zonal atmospheric circulation and prevailing western winds are primary drivers. The climate is further influenced by the movement of weather fronts and the presence of both high-pressure and low-pressure areas.
• Continental and Topographical Factors:     * The vast land mass of the Eurasian continent contributes to the climatic profile.     * The Carpathian mountains serve as a physical barrier for longitudinal air flow and advection.

Classification and General Characteristics of Polish Climate

• Scientific Classifications:     * Okołowicz: Defines the climate as a temperate warm transitional climate.     * Koeppen: Classifies it as a warm summer humid continental climate, also known as a hemiboreal climate (type $Dfb$).
• Weather Variability:     * Highly variable weather conditions.     * Moderate to high spatial variety of climate between different regions.     * Significant variability on day-to-day, seasonal, and annual scales.

Main Pressure Systems and Air Masses

• Pressure Systems: The Polish climate is dominated by the Azores High, the Icelandic Low, and the Siberian High.
• Primary Air Masses:     * Continental Polar ($cP$)     * Maritime Polar ($mP$)     * Arctic ($A$)     * Tropical ($T$) originating from the Mediterranean region.
• Air Mass Frequency (source: Kaczorowska 1986):     * Arctic ($A$): Winter ($11\%$), Spring ($16\%$), Summer ($2\%$), Autumn ($10\%$), Year total ($10\%$).     * Maritime Polar ($mP$): Winter ($46\%$), Spring ($33\%$), Summer ($60\%$), Autumn ($45\%$), Year total ($46\%$).     * Continental Polar ($cP$): Winter ($37\%$), Spring ($45\%$), Summer ($34\%$), Autumn ($38\%$), Year total ($38\%$).     * Tropical ($T$): Winter ($1\%$), Spring ($1\%$), Summer ($0\%$), Autumn ($0\%$), Year total ($0.5\%$).     * Transformed: Winter ($5\%$), Spring ($5\%$), Summer ($5\%$), Autumn ($7\%$), Year total ($5.5\%$).

Seasonal Changes and Thermal Transitions

• Astronomical Seasons: Poland experiences four distinct astronomical seasons: Spring, Summer, Autumn, and Winter.
• Thermal Seasons (according to Romer):     * Pre-Spring: $0,0\,^{\circ}C < t \leq 5,0\,^{\circ}C$     * Spring: $5,0\,^{\circ}C < t \leq 15,0\,^{\circ}C$     * Summer: $t \geq 15,0\,^{\circ}C$     * Autumn: $5,0\,^{\circ}C < t \leq 15,0\,^{\circ}C$     * Pre-Winter: $0,0\,^{\circ}C < t \leq 5,0\,^{\circ}C$     * Winter: $t \leq 0,0\,^{\circ}C$
• Annual Temporal Patterns:     * Warm Period: April to September.     * Cold Period: October to March.     * Precipitation: Reaches its highest levels in the Summer and lowest levels in the Winter.     * Pressure Dynamics: The highest number of pressure systems and weather fronts occur during Autumn and Winter.     * Temperature Extremes: Highest temperatures typically occur in July, and the lowest in January.

Precipitation Dynamics and Trajectories

• Low-Pressure System Trajectories (Van Bebber 1888):     * Trajectory IVb: This is the most common trajectory, affecting Poland primarily through weather fronts.     * Trajectory Vb: Responsible for many deep low-pressure systems.
• Moisture Sources: High precipitation is frequently associated with moist air masses originating from the Great Hungarian Plain.
• Impact: These systems are often responsible for heavy rainfalls and subsequent floods.

Regional Differentiation of Climate

• East-West Gradient: Continentalism progresses as one moves towards the East.     * Western Poland: Frequently affected by maritime Polar ($mP$) air masses; generally features the most favourable climate conditions (especially in the South-West).     * Eastern Poland: Often affected by continental Polar ($cP$) air masses.
• Maritime and Mountainous Influences:     * Baltic Sea: Exerts climate influence in its close proximity.     * Highlands and Mountains: Characterized by less favourable climate conditions compared to the rest of the country.
• Bioclimatic Stimulation (Okołowicz, Martyn 1995): The Baltic seaside and Polish mountains possess the strongest stimulative bioclimate, categorized across regions as strong, medium, or weak.

Climate of the Polish Mountains

• General Features:     * Characterized by lower minimum and maximum temperatures than lowland areas.     * Displays higher weather contrasts and stronger winds.     * Altitudinal zonation is present, with certain properties of an Alpine climate.
• Specific Wind and Pressure Conditions:     * Foehn Wind: Known as the "Halny" in the Tatra mountains.     * Pressure Dynamics: Sudden drops in atmospheric pressure often precede storms.     * Air Movement: Atmospheric waves (e.g., lee waves) influence cloud formation.
• Phenomena Frequency:     * Calms: Lower frequency in mountains; higher frequency in valleys, canyons, and basins.     * Inversions: Common thermal inversions occur in valleys and basins.     * Extreme Events: Increased frequency of thunderstorms, fog, mist ("sea of mists"), heavy rain, snowfall, blizzards, and hard rime.     * Optical Phenomena: Brocken spectre and glory rings are noted in mountain regions.

Climate Change Trends and Impacts

• Observed Changes:     * Increased occurrence of severe weather phenomena.     * Heightened thermal and hydrological hazards.     * Decreased total sums of precipitation coupled with high variability.     * Increased seasonal and annual extreme temperatures.
• Consequences for Human Society:     * Health: Negative health impacts, decreased life expectancy, and increased mortality.     * Resources: Increased consumption of water and electricity.     * Economy: Economical impacts and disturbances in infrastructure and transportation systems.

Urban Climate Specifics (Case Study: Warsaw)

• Natural vs. Urbanised Areas:     * Natural: Features high photosynthetic activity, carbon dioxide absorption, oxygen production, heat transfer in underbrush, and high interception/evapotranspiration.     * Urbanised: Reduced photosynthetic activity, low interception, no throughfall, low evaporation/transpiration, and high impermeability.
• Urban Phenomena:     * Anthropogenic Factors: Heat production and transfer, increased air pollution, and reduced oxygen.     * Anomalies: Urban Heat Island (UHI) and Urban Cold Island (UCI); occurrence of dust domes and thermal plumes.     * Insolation: Decreased irradiance and insolation compared to rural areas.
• Warsaw Specific Data:     * Solar Radiation: Differences in Global Solar Radiation (GSR) between the urban station (IGF UW) and rural station (Belsk) recorded between 2008-2014 show significant daily sum variations ($MJ \cdot m^{-2}$).     * Future Projections: Scenario 8.5 (Warsaw City Hall Office) predicts a high annual number of days with $T_{min} > 20\,^{\circ}C$ for the years 2081-2090.

Required Climate Actions

• Assessment:     * Exposure: Evaluating present and future exposure to negative climate conditions.     * Vulnerability: Assessing the susceptibility of city infrastructure and inhabitants to climate change.
• Mitigation (Reducing Changes):     * Increase green areas.     * Protect building-free zones through strict development policy.     * Promote zero-emission vehicles and reduce traffic.     * Transition away from fossil fuels for energy.     * Implement energy-saving and heat-saving technologies.
• Adaptation (Adjusting to Changes):     * Conduct infrastructure audits and upgrades to ensure operational capacity under extreme conditions.     * Adjust city administration, industry, and services to expected conditions.     * Monitor and troubleshoot hotspots before sociological or economical functions are severely impacted.

Extreme Weather Events in Poland

• Types of Phenomena: Floods, heavy rains, flash floods (particularly in cities), hail, heat waves, cold waves, severe thunderstorms, tornadoes, downbursts, and squall lines.
• Temporal and Spatial Patterns:     * Most extreme events occur during the warm period (Spring and Summer).     * High risk is associated with cyclonic circulation and advection from the south-eastern quadrant.     * Directly related to the buoyancy of air masses and Convective Available Potential Energy (CAPE).
• Tornadoes: Records (Leziak 2014) indicate specific risk zones for high winds (excluding mountain peaks) and catalog the annual number of tornado cases in Poland.