2001: Storms in the Future: Changes in Intensity, Cloudiness, Rainfall and Economic Costs

This project deals with the question of how weather conditions in the world's middle latitudes will be different in a possible future warmer climate. In the midlatitude regions, where most of the world's population lives, the major weather-makers are midlatitude storms that mix cold and warm air masses and produce high winds, clouds, and precipitation. In order to explore how different the midlatitude weather of a warmer world will be from the weather that we experience today, it is important to understand how the properties of midlatitude storms may change as climate warms.

Midlatitude storms are disturbances that form along the jet-stream (the river of air that circumnavigates the globe in the Northern and Southern midlatitudes) and travel with it in an eastward direction. The jet-stream owns its existence and draws its energy from the large temperature differences that exist between the Earth's equator and poles. In a warmer climate, the temperature difference between those two regions will be smaller and this may result in a slower, less energetic jet-stream. Does this mean that a warmer world will experience fewer or weaker midlatitude storms? Keep in mind that storms are fueled by the presence of humid air masses in their path, a condition that will be more prevalent in a warmer climate.

In our attempt to profile the storm of the future, our group will build on the knowledge that can be gained from studying the storms of the past and on predictions made using the GISS climate model. We have developed tools that scan weather data to locate and track midlatitude storms as well as tools that collocate and correlate storm and cloud properties from weather and satellite observations, and we have developed a thirty year climatology of storms. We will use those tools to fulfill the following objectives:

1. Examine how storm frequency and intensity has been changing in the last 30 years, and identify periods within those years when the Northern midlatitude regions were warm/cold and the temperature difference between the Northern low and high latitudes was small/large.
2. Examine the differences in the frequency and intensity of midlatitude storms between those warm and cold time periods.
3. Examine how the presence of a stronger or weaker storm changes the probability that a person on the ground will experience thinner-drizzling, or thicker-raining clouds.
4. Examine how well the GISS climate model reproduces the observational storm behavior, both in terms of the storm changes with climate and of the relations between storm strength and cloud type distribution.
5. Use the GISS climate model to examine changes in storm properties in a warmer climate scenario.
6. Use insurance records to examine how storm-related damage costs have been changing in the last 30 years and how those cost changes may relate to variations in storm intensity and frequency.

Combining the different parts of our analysis we will attempt to resolve how the frequency and strength of midlatitude storms will change in a warmer climate and what such changes will mean in terms of the everyday weather conditions in the midlatitude regions.

Guiding Science Questions and Related Tasks

How have storm frequencies and intensities changed in the past 50 years?

Task: Plot trends in storm frequency and intensity over the last 50 years for the different seasons of the year. (Chris, Heberthe)

How are storm frequencies and intensities different during warm and cold years?

Task: Plot storm intensity distributions for cold and warm years and compare them. (Chris, Heberthe)

How well is the GISS GCM simulating storm frequencies and intensities?

Task: Plot maps of storm frequency and intensity from GCM simulations and compare with observations. (Chris, Heberthe)

What is the GISS GCM telling us about changes in storm frequency and intensity with global warming conditions?

Task: Compare storm frequencies and intensities in a current climate and a global warming simulation of the GISS GCM (Chris, Heberthe)

How does the intensity of a storm relate to the properties of the clouds and the amount of rain produced by the storm?

Task: Examine storm observations and relate the intensity of the storms with the optical properties of the clouds and the amounts of precipitation. (Abdu, Ali)

How has economic damage from storms been changing in the last 30 years?

Task: Plot trends of storm damage for the US over the last 30 years. (Abdu, Kinga, Shaynah)

How are storm damage costs related to the intensity of the storms?

Task: Examine periods of high and low storm damages and compare the properties of the storms during those periods. (Abdu, Kinga, Shaynah)

Related Science Principles

High and low pressure systems in the atmosphere (Physics/Earth Science)

Corriolis force/ Pressure gradient force (Physics/Earth Science)

Relationship between the atmospheric pressure gradient and wind speed/direction (Physics/Earth Science)

Cloud formation processes/Condensation of water vapor (Physics/Chemistry/Earth Science)

Basic Science Questions

Why are there pressure differences in the Earth's atmosphere?

How do these pressure differences make winds?

How do winds lead to storms?

How do storms make clouds?