On Future Changes in Mediterranean Winter Temperatures, Precipitation and Relative Humidity

Inhaltsverzeichnis (Table of Contents)

• 1. Introduction
• 2. The representative Concentration Pathways
• 3. Origin of the data
• 4. Future periods 2021 – 2050 and 2071 - 2100
  • 4.1 Winter mean temperatures
  • 4.1.1 Warm and cold days
  • 4.2 Extreme values of the maximum and minimum temperatures
  • 4.3 Annual mean relative humidity
  • 4.4 Annual mean precipitation
• 5. Reference period 1971 – 2000
  • 5.1 Winter mean temperatures
  • 5.1.1 Warm and cold days
  • 5.2 Extreme values of the maximum and minimum temperatures
  • 5.3 Annual mean relative humidity
  • 5.4 Annual mean precipitation
• 6. Differences between reference and future periods
  • 6.1 Differences in winter mean temperatures
  • 6.1.1 Differences in warm and cold days
  • 6.2 Differences of the extreme values
  • 6.3 Differences in relative humidity
  • 6.4 Differences in precipitation

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis aims to analyze the projected changes in Mediterranean winter temperatures, precipitation, and relative humidity under the RCP 2.6 W/m² scenario, comparing future periods (2021-2050 and 2071-2100) to a reference period (1971-2000). It also explores the characteristics of Representative Concentration Pathways (RCPs), focusing on RCP 2.6.

• Projected changes in Mediterranean winter climate variables under RCP 2.6.
• Comparison of future climate projections with historical data.
• Analysis of extreme temperature values and their trends.
• Assessment of changes in relative humidity and precipitation patterns.
• Evaluation of RCP 2.6 in the context of the Paris Agreement's climate goals.

Zusammenfassung der Kapitel (Chapter Summaries)

1. Introduction: This chapter introduces the thesis's focus on the Mediterranean region (30°N - 50°N and 10°W - 45°E) and its climate characteristics. It poses the central research question: How will RCP 2.6 W/m² affect near and far future climate compared to the 1971-2000 reference period? The chapter highlights the Mediterranean's vulnerability to climate change, emphasizing the potential for increased droughts and heatwaves due to decreasing precipitation and rising temperatures. It establishes the context of the research by referencing previous studies on Mediterranean climate change and situates the study within the larger context of global climate change.

2. The representative Concentration Pathways: This chapter details the Representative Concentration Pathways (RCPs), focusing on RCP 2.6. It explains the four RCP scenarios (2.6, 4.5, 6, and 8.5 W/m²) and their radiative forcing projections. It provides a comprehensive description of RCP 2.6, also known as the RCP 3-P.D. (peak and decline) scenario, explaining its unique characteristic of peaking and then declining radiative forcing. The chapter also outlines the modeling methodologies and underlying assumptions of the RCPs and their connection to the Paris Agreement’s climate goals. The detailed description of the models and parameters used to develop the scenarios is provided in this chapter. Additionally, the relationship between historical data (SRES) and projected future trends in various climatic indicators (like GHG emissions, sea-ice, and ocean warming) are discussed for various scenarios.

3. Origin of the data: This chapter describes the data sources and methodologies used in the thesis. The data, obtained from the Earth System Grid Federation (ESGF) via Linköping University, encompasses temperature, precipitation, and relative humidity variables for the Mediterranean region. The chapter explains the CMIP5 project and its role in providing climate data. It details the CORDEX project's high-resolution downscaling techniques and the use of EC-Earth as the driving GCM and RCA4 as the RCM. The chapter meticulously describes the data's resolution, ensemble (r12i1p1), and the utilized models (EC-Earth, RCA4, NEMO, LIM2, IFS, TESSEL, and OASIS3), providing a deep insight into the modelling process and data quality.

4. Future periods 2021 – 2050 and 2071 - 2100: This chapter presents the analysis of climate data for the future periods (2021-2050 and 2071-2100). The data is processed to calculate various parameters such as time mean, annual mean, and zonal mean, for temperature, precipitation, and relative humidity. The chapter provides detailed analysis of these parameters for each future period, and uses the data to quantify the projections of the climate variables, providing detailed information about the methodologies and data treatment in the study. The chapter also analyzes the percentage of warm and cold days based on the 95th and 5th percentiles of the reference period.

5. Reference period 1971 – 2000: This chapter presents the analysis of climate data for the reference period (1971-2000), using the same parameters and methodologies as in Chapter 4. It provides a detailed baseline description of the climate conditions during the reference period, serving as the foundational data set against which future projections are compared. The chapter analyses the data in the same manner as Chapter 4 with the same parameters to establish clear comparison and highlight differences between the reference period and future projections.

6. Differences between reference and future periods: This chapter presents a comparative analysis, focusing on the differences between the future periods (Chapters 4) and the reference period (Chapter 5). The analysis includes the differences in winter mean temperatures, warm and cold days, extreme values, relative humidity, and precipitation. This detailed comparison quantifies the projected changes in each climate variable for both near and far future periods and highlights the magnitude and spatial distribution of these changes. The significance of these differences, based on confidence levels, are provided.

Schlüsselwörter (Keywords)

Mediterranean climate, RCP 2.6, climate change projections, temperature, precipitation, relative humidity, extreme weather events, CORDEX, CMIP5, EC-Earth, RCA4, Paris Agreement, global warming.

Frequently Asked Questions: Analysis of Projected Changes in Mediterranean Winter Climate under RCP 2.6

What is the main focus of this thesis?

This thesis analyzes projected changes in Mediterranean winter temperatures, precipitation, and relative humidity under the RCP 2.6 W/m² scenario. It compares future periods (2021-2050 and 2071-2100) to a reference period (1971-2000) to understand the impacts of climate change in the region.

What is the geographical area covered by the study?

The study focuses on the Mediterranean region, specifically the area between 30°N - 50°N latitude and 10°W - 45°E longitude.

What climate variables are analyzed?

The analysis covers winter mean temperatures, extreme values of maximum and minimum temperatures, annual mean relative humidity, and annual mean precipitation.

Which Representative Concentration Pathway (RCP) is used in this study?

The study utilizes RCP 2.6 W/m², also known as the RCP 3-P.D. (peak and decline) scenario, which projects a peak and subsequent decline in radiative forcing.

How are future climate projections compared to historical data?

Future climate projections (2021-2050 and 2071-2100) are compared to a reference period (1971-2000) to quantify the changes in each climate variable and assess the magnitude and spatial distribution of these changes.

What data sources and methodologies were used?

Data was obtained from the Earth System Grid Federation (ESGF) via Linköping University. The CMIP5 and CORDEX projects provided climate data, with EC-Earth as the driving GCM and RCA4 as the RCM. High-resolution downscaling techniques were employed. The models used include EC-Earth, RCA4, NEMO, LIM2, IFS, TESSEL, and OASIS3.

What are the key findings of the study regarding temperature changes?

The study details projected changes in winter mean temperatures, including an analysis of warm and cold days based on the 95th and 5th percentiles of the reference period, for both near and far future periods. The differences between these periods and the reference period are analyzed in detail.

What about precipitation and relative humidity changes?

The study provides a detailed analysis of changes in annual mean relative humidity and annual mean precipitation for both future periods and compares them to the reference period. The differences are quantified and their significance discussed.

How does the study relate to the Paris Agreement?

The study evaluates RCP 2.6 in the context of the Paris Agreement's climate goals, as RCP 2.6 represents a scenario consistent with limiting global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels.

What are the key takeaways of the thesis?

The thesis provides a comprehensive analysis of projected changes in Mediterranean winter climate under RCP 2.6, highlighting the potential impacts of climate change on the region, including increased droughts and heatwaves. The findings offer valuable insights for climate change mitigation and adaptation strategies.