This remarkable conclusion by a panel of over 500 scientists should shift the focus of the climate community, from global warming to the next major challenge of predicting regional climate changes. The major factors that limit our ability to predict regional climate changes greenhouse gases" and 2) "representation of climate processes in models, especially feedbacks associated with clouds, oceans, sea ice and vegetation.."

Center Rationale: C⁴ is in a unique position to mount an ambitious but focused changes. The articulated research program, on aerosols-ozone forcing, cloud feedback and regional climate, cannot be developed through normal modes of funding. It requires close collaboration across institutional and national boundaries; environmental problems transcend such boundaries. Prime examples of the Science and Technology Center(STC)- style research at C⁴ are the Central Equatorial Pacific Experiment (CEPEX) conducted in 1993 and the proposed Indian Ocean Experiment (INDOEX).

INDOEX, involving institutions from France, Germany, India and Netherlands, will give us a first look at how a human population of 1 billion in the Indian sub-continent is modifying the climate forcing factors, involving aerosols, ozone and clouds. If successfully completed, INDOEX would be one of the best examples of how the STC structure is enabling academics and students to address big interdisciplinary problems and transfer this knowledge to the future generation of researchers.

Scope of Research: We seek to integrate observations and field-tested hypotheses (See figure on cover page) with models used for climate predictions. We identify gaps in current observing systems; fill these gaps with new data; and integrate these into global observing systems and modeling activities. This strategy requires a complex array of observations from aircraft, surface, buoys, ships and satellites. A state-of-the-art data integration and archival system is required to integrate the data and facilitate fast access. Lastly, numerical models of aerosols and clouds and the coupled ocean/atmosphere system are needed to link the observations with climate related processes.

Distinguishing Feature: C4 has successfully leveraged and coordinated its research projects with American and European institutions. The cost of the proposed INDOEX field phase is about 3 times the funds requested in this proposal. C4 was able to secure and coordinate such large commitment of resources from participating institutions and other agencies, primarily because it significantly leverages the ongoing activities within these institutions.

Goal: To develop the theoretical, observational and modeling framework for representing cloud, aerosol and chemical processes and their related climate forcing for the prediction of global and regional climate changes .

Overall Objectives: 1) to identify and quantify the regional radiative forcing due to aerosols and ozone in pristine and polluted environments; 2)to characterize and parameterize the cloud-radiation-photochemical interactions in the tropical convective- cirrus systems and the extra-tropical storm track cloud systems; 3) To understand the role of aerosol forcing and cloud feedbacks in regional climate changes. The plan for achieving these overall objectives involves four specific tasks:

(i)Extend the models and the CEPEX data base developed for the pristine, low ozone and aerosol-poor equatorial Pacific to the relatively polluted, high ozone and aerosol- rich tropical Indian ocean. This task will be accomplished through INDOEX. This field experiment will collect data from research cruises, island stations, satellites and multiple aircraft.

(ii) Create three new infrastructure components: a) develop the C4 Integrated Data System for combining CEPEX and INDOEX data sets with other data sets (see inside cover page); b) Use INDOEX instruments to create the La Jolla CARPOS(cloud-aerosol- radiation-pollution observing system) site; and c) develop a state-of-the-art 3-dimensional radiative transfer model for clouds and aerosols.

(iii) Develop the framework for linking the N. Hemisphere extra-tropical storm track cloudiness and their radiative forcing with large scale dynamical fields. These systems are likely to prove crucial for modeling the mid-latitude climate.

(iv) Conduct a regional climate change study with the NCAR Climate System Model(CSM) model. Changes in two regions, in response to global warming, will be emphasized: i) the INDO-Pacific warm ocean region, and ii) the eastern US, north Atlantic and western Europe. Climate changes in these two regions are of scientific and national interest and, also, provide a critical test for the models developed by the center scientists.

Education: C⁴ will conduct a broad spectrum of educational programs spanning K-12, 2-year community college, undergraduate and graduate to post-doctoral level education. In collaboration with the Scripps Institution of Oceanography (SIO)Ős Stephen Birch Aquarium-Museum (D. Baxter), C4 will continue the successful program on global change for K-12 science teachers, which so far has resulted in a global change book for K- 12 teachers. Other proposed efforts include: Summer research internship program for community college science teachers in San Diego; research and software development experience for under graduate students; summer course in Climate modeling for graduate students and advanced researchers; NATO advanced institute on environmental problems; and several international INDOEX workshops in the US, Germany , France and India. Finally C4 will play a leading role in the new curricular program at SIO in climate and atmospheric sciences, which it helped create.

Outreach and Knowledge Transfer: Our main outreach efforts will involve national laboratories such as NCAR, mission agencies such as DOE and NASA. The CIDS will be used to aid GCM modeling efforts at NCAR and to guide radiation modeling efforts at the DOE-Atmospheric Radiation Measurement (DOE-ARM) . The CIDS tropical databasei efforts are leading to novel strategies for combining large volumes of satellite data with correlated data from many in situ platforms. This development could serve as one of the many real-life prototypes for national and international efforts in global observing systems.

Institutional Commitment: UCSD-SIO has made major commitments to C4 for the third term. It has provided a new building to house the center. It has created a new research unit, the Center for Atmospheric Sciences that houses C4 and other related atmospheric sciences research activities in SIO and UCSD. SIO has provided salary for the participation of its faculty, and Vetlesen Foundation funds for administratorŐs salaries, instrumentation and computing equipment. The Institution has also approved a research position in the area of aerosol chemistry and a senior faculty position in the atmospheric sciences. These are in addition to the 5 tenure-track 5 scientists hired during the first 5 years of C4. In addition, salaries of participants at MPI, NCAR, Oregon State, U. Maryland and Utrecht are being borne by the respective institutions.