1998: Clouds Over Storm Lifecycles

Researchers: Jose Alburquerque, Andrew Audry, Sharika De La Oz, Anthony Del Genio, Robert Kruckeberg, Haidy Pena, Chris Petersen, William Rossow, Jericco Tolentino, and George Tselioudis.

If the Earth's climate is changing, what will happen to the clouds? Will more clouds form? Will these clouds warm or cool the planet? Climate researchers use computer models to simulate and predict future climate change. However, these climate models have a difficult time simulating large-scale cloud systems and the storms that produce them. The primary objective of the Clouds project is to better understand how the atmospheric processes in mid-latitude storms generate different types of clouds. This will allow climate modelers to improve their ability to simulate clouds in future climate change scenarios.

Project Goal for 1998-99

The Clouds project aims to study real world storm systems under extreme conditions of climate. These conditions will be indexed with respect to historical trends in differences of temperature between low and high latitudes, where small temperature differences are indications of a warmer climate (Gitelman et. al., 1997). Modeling experiments have indicated that a warmer climate may produce storms of higher intensity (Carnell and Senior, 1998). The Clouds project will attempt to validate this relationship using historical ground observations from the National Centers for Environmental Prediction (NCEP) reanalysis dataset. Periods of higher intensity storms will be identified. Using data from the International Satellite Cloud Climatology Project (ISCCP), high intensity mid-latitude storm clouds will be compared to similar systems generated in the climate model. These same mid-latitude cloud systems will also be compared to tropical hurricane systems that have simpler cloud structures. These comparisons will result in a better awareness of climate model deficiencies, leading to the improvement of cloud modeling that can enhance predictions of climate change.

Science Questions

1. What is the relationship between latitudinal temperature differences and mid-latitude storm intensity?
2. Which historical periods produce real world storms of higher intensity?
3. How can we describe the evolution of cloud types produced in high intensity storm systems?
4. How well does the GCM simulate cloud formation for high intensity storm systems?

Hypotheses

1. A warmer climate will result in smaller latitudinal temperature differences, causing lower storm frequency but higher storm intensity in the mid-latitudes.
2. High intensity real world storm systems will produce a wide range of cloud types, with a large number of deep convective clouds, as well as cirrus cloud formation due to slant wide convection along warm fronts. Storms in the climate model will also produce a significant amount of deep convective clouds, but will result in a more narrow distribution of cloud types, and remain deficient in cirrus cloud formation.

Research Tasks

1. Identify historical periods that produce storms of highest intensity.
2. Determine the relationship between low to high latitude temperature differences and mid-latitude storm intensity
3. Describe the evolution of cloud types produced in high intensity mid-latitude storms.
4. Establish differences between observed storm cloud formation and GCM cloud formation for high intensity storm systems.
5. Continue analyzing hurricane systems to establish correlations between parameters such as storm strength index and the formation of various cloud types.
6. Establish correlations between hurricane cloud distributions and high intensity mid-latitude cloud distributions.
7. Continue software development and support of Java applet tools for accessing storm cloud data (NCEP, ISCCP, and GCM).
   • Develop a GIF image processing routine to save and print color plots for storm cloud data.
   • Develop software for the acquisition and inspection of daily hurricane observations.
   • Assist in the comparison between observed and GCM storm clouds in order to develop software for correlating cloud distribution types between these observed and modeled storms.

Data

1. NCEP reanalysis parameters: sea level pressure, surface temperature
2. ISCCP parameters: cloud optical thickness, cloud top pressure
3. GCM parameters: sea level pressure, cloud optical thickness, cloud top pressure