RESEARCH ADVANCES

Following are comments by ICESS PIs on the advances made by their research groups over the past year:

Frank W. Davis: (Link to: http://www.biogeog.ucsb.edu/top.html)

Our major research accomplishments for the year occurred in four areas: conservation planning, image classification, predicting wildlife species distributions, and analyzing historical fire regimes. Several advances were made in optimal siting of potential new nature reserves. A location-allocation model developed originally for the Sierra Nevada Ecosystem Project was successfully adapted to a real planning application with The Nature Conservation in the Columbia Plateau ecoregion.

The Maximal Covering Location Problem formulation of the reserve siting problem was enhanced to allow weighting of species or sites and by integrating the model into a commercial geographic information system to improve its utility to conservation planners. A new algorithm for classifying digital satellite images was developed that makes use of existing map information. This technique was applied both in mapping a large ecoregion and in detecting changes in land cover over time. The land-cover map of the Intermountain Semi-Desert ecoregion in portions of nine states allowed us to complete the nation's first multi-state gap analysis, or conservation assessment of vegetation types. In the area of wildlife modeling, the habitat-based approach has been refined to encompass habitat factors over the length scale of the species' home range rather than at each individual location. A statistical technique was adapted to analyze the extreme events in the fire history of a national forest to determine whether modern fire suppression has changed the fire regime.

Tommy D. Dickey: (Link to: http://www.icess.ucsb.edu/~tommy)

The Ocean Physics Laboratory (OPL), which focuses on interdisciplinary ocean observations using new techniques, joined ICESS in January 1996. The group has deployed instrumentation in several of the world's oceans. Example locations include: the equatorial Pacific, the central Pacific, near Wawaii, the eastern North Atlantic (near Iceland), the Sargasso Sea (34 70 and near Bermuda), the Mediterranean Sea, the Arabian Sea, coastal California, and off the coast of Massachusetts. Studies have dealt with biogeochemical cycling related to climate change, upper ocean dynamics, the ecology of the upper ocean, and coastal pollution. The OPL recently completed field measurements (10 months) in the Arabian Sea observing the major monsoons, observing two different mixing processes and bio-optical variability associated with these effects during this experiment. The OPL continues its leadership of the Bermuda Testbed Mooring (BTM) program. Hurricane Felix passed over the BTM in August 1995, providing what is believed to be the first time series of temperature and currents under such intense forcing conditions in the open ocean. Two hurricanes passed over the Coastal Mixing and Optics mooring site south of Cape Cod within two weeks in the fall of 1996. More information on OPL activities may be found on the web site http://www.icess.ucsb.edu/~tommy.

Mountainous areas, particularly in the western U.S., supply a large fraction of the freshwater resources through snowmelt, and they are especially sensitive to changes in climate and precipitation chemistry. Our research on the hydrology and hydrochemistry of alpine drainage basins is part of NASA's Earth Observing System. We combine three methods: observations in the field and laboratory; measurements from remote sensing; and models of hydrologic processes and chemical transformations. Important findings are in three major areas: models of snowmelt runoff and watershed chemistry, alpine regions as indicators of climate change, and remote sensing of snowpack characteristics.

Our basin-scale hydrologic models can forecast spring melt and predict a watershed's response to changes in snow amount, temporal and spatial distribution of snow versus rain, and precipitation chemistry. We also connect our hydrologic models to climate model scenarios of regional changes.

The EOS Amazon Project has been analyzing and modeling the hydrology of the entire Amazon River Basin with a particular emphasis on defining regional evaporation fields from ground-level hydrometric data and on using satellite-based data to drive a model of the basin-wide water and energy balance. The group has also begun exploratory fieldwork to isolate the impact of land use on river hydrology and biogeochemistry in Rondonia State, one of the major foci of intense deforestation in Amazonia. The focus on land-use impacts at the scale of river basins thousands of square kilometers in extent will be a contribution to the Large-scale Atmosphere-Biosphere Experiment in Amazonia (LBA) after 1997.

Catherine H. Gautier: (Link to: http://www.icess.ucsb.edu/esrg.html)

There are four areas where my group has made significant progress over the last year: 1) effects of cloud heterogeneity on 3-D radiation field, 2) radiative transfer modeling in the Near IR, 3) modeling of surface/cloud interactions over the Antarctic, and 4) neural net application to the determination of the global heat and water fluxes.

We have numerically demonstrated that cloud heterogeneity can significantly affect the absorption of solar radiation in a cloudy atmosphere. These effects need to be taken into account in climate models if they are to be accurate in predicting future climates. We have developed a new Near IR model initially tuned for the AIRS instrument to be launched on the EOS PM platform in order to help in the detection of low clouds. We have shown that the multiple reflections that occur when clouds are present over the highly reflecting surface of the Antarctic can modify the spectral nature of the radiation reaching the surface. When the ice melts, these multiple reflections decrease and the UV radiation environment changes. Our results indicate that, in coastal Antarctic regions, both surface and satellite observations cannot be interpreted without accounting for the existence of different surface types in the vicinity. Radiation observations near the coast over the ocean are affected by the presence of snow and ice regions nearby; similarly, measurements at coastal stations are affected by the presence of open ocean nearby. This effect, which can reach 10%, is felt up to 10 km from the coast. Finally, we have notably improved the accuracy of satellite-derived near-surface parameters such as atmospheric humidity and temperature with a new neural network approach. Global fields of latent and sensible heat fluxes can now be obtained with an accuracy similar to that of ships.

David A. Siegel: (Link to: http://www.icess.ucsb.edu/bbop/bbop.html
http://www.icess.ucsb.edu/PnB/PnB.html)

The ocean optics research group has been investigating ocean color remote sensing and the heating of the upper ocean. We have produced new mathematical algorithms to invert satellite ocean color spectra into useful quantities for assessing upper ocean photoprocesses. In particular, we have discovered an important seasonal cycle in colored dissolved organic materials (CDOM) in the blue Sargasso Sea where CDOM was thought to be absent. The seasonal changes in CDOM seem to regulate the amount of dimethyl sulfide in surface waters (due to photo-oxidation) which is an important source for cloud-condensing nuclei in the open ocean. The BBOP observational program is on-going.

In analyzing ocean optical data taken in the western equatorial Pacific Ocean during the massive TOGA/COARE experiment, we demonstrated that upper layer heat budgets are regulated strongly by changes in the penetration of the solar radiation flux to depth. Changes in solar penetration are caused by the amount of phytoplankton biomass in the water column and, to a lesser degree, by clouds. This provides an interesting feedback between ocean biology and physics where increasing algae abundances cause more heating of the upper water column, which in turn increases evaporation and convection in the lower atmosphere. Hence, we suggest that more biology should correspond to more clouds.

Last, we (Profs. Siegel, Smith, Washburn, Brzezinski, and Mertes) have initiated an observational project in the S.B. Channel in collaboration with the NOAA Channel Islands National Marine Sanctuary. This project will investigate the relationship between sediment PLUMES and phytoplankton BLOOMS on the ocean color of the local coastal waters. This project has demonstrated how different local community organizations can work efficiently together on research projects.

Raymond C. Smith: (Link to: http://www.icess.ucsb.edu/lter/lter.html)

The U.C. Marine Bio-Optics (UCMBO) group has focused considerable effort during the past year on Antarctic research. As part of the Palmer Long-Term Ecological Research (LTER) program, aimed at understanding the marine ecology of the Southern Ocean, significant findings include: a model of the spatial and temporal variability of phytoplankton production in the Western Antarctic Peninsula (WAP) area and a reassessment of primary production of the whole Southern Ocean based upon biogeochemical provinces; a study of surface air temperature and sea ice climatologies that show statistically significant warming trends for the WAP region over the past half century, a significant anti-correlation between surface air temperature and sea ice extent, and a long-term persistence in monthly sea ice and surface air temperature anomalies, wherein consecutive high ice/low temperature years are followed by consecutive low ice/high temperature years, a pattern which is coherent with the Southern Oscillation Index (SOI). This LTER sea ice record provides a basis against which life-history parameters of primary producers and populations of key species from different trophic levels can be monitored and against which oceanographic and atmospheric variability in this region can be compared and modeled. Further, because sea ice-temperature-SOI relationships appear to be strongly linked in this region, the Palmer area has been shown to be ideally suited to study ecological responses to climate variability.

The MODIS LST Group has developed new LST algorithms (the generalized split-window LST algorithm by Wan and Dozier, 1996; the day/night LST algorithm by Wan and Li, 1997) for retrieving land-surface temperature and emissivity from EOS MODIS data and MODIS Airborne Simulator (MAS) data. Thermal infrared instrumentation and methodology have been developed to measure the spectral emissivity and temperature of terrestrial materials in the laboratory and in the field. In the past year, three field campaigns with MAS flights were conducted for validating the MODIS LST algorithms, giving very encouraging results.

Libe Washburn: (link to: http://www.icess.ucsb.edu/iog.html)

The Interdisciplinary Oceanography Group has been working on a number of new research projects over the past year. A major research effort has been establishing an array of three high frequency radar stations along the Santa Barbara Channel coast to observe the evolving structure of surface currents (project funded by W.M. Keck Foundation and the Minerals Management Service). Two sites have been established: one at Coal Oil Point near UCSB and another at the lighthouse at Point Conception. These will be used to interpret spatial patterns of recruitment of marine organisms into the inter-tidal zone. They will also be used to gather statistics of currents to predict the dispersion of oil in the event of a spill in the Channel. A second project is examining the hydrodynamic factors affecting the dispersal of kelp spores in tidal reef communities (project funded by NSF). We have been working with colleagues in the Marine Science Institute and UC Santa Cruz in this work. Our field site is on the seafloor off Summerland and contains instrumentation for measuring ocean currents and turbulence in the vicinity of an array of kelp plants. Divers from our group, including the principal investigators (Daniel Reed and LW), regularly visit the site. A third project is directed at understanding the dispersal and toxicity of storm water runoff plumes in Santa Monica Bay (project funded by NOAA/Sea Grant, the County of Los Angeles, and the City of Los Angeles). We participated in two sets of cruises during winter storms in 1996-1997. Oceanographic measurements were made offshore of the Malibu Creek watershed and the Ballona Creek watershed and revealed extensive, toxic plumes due to runoff. Our data is being used by agencies in Los Angeles to make policy decisions on stormwater management. A fourth project is a study of natural hydrocarbon seepage off Coal Oil Point (project funded by the Minerals Management Service and the University of California Energy Institute). A principal goal of this research is to quantify the flux of gasses from the seafloor to the ocean and atmosphere. These gasses are an important source of ozone, an air pollutant, in Santa Barbara County. Our preliminary results indicate that current inventories of natural seepage are underestimates; we are finding that the seeps contribute about the same amount of reactive organic gasses as all mobile sources in the County.