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 three areas:
1) conservation planning and assessment
2) assessment of risk to biodiversity
3) monitoring land-cover change
In the area of conservation planning, we published a protocol for the U. S. Forest Service for siting new research natural areas and tested the method on Los Padres National Forest. The Biogeography Lab also hosted the 8th Annual Meeting of the National Gap Analysis Program at UCSB. More than 110 people attended the meeting, with foreign attendees from Mexico, Korea, Sweden, Canada, and Portugal. The California Gap Analysis was completed and the GIS database and report were published on the World Wide Web. An interactive CD-ROM version of the database will be published later this year for the general public. We completed two studies that used spatial data to assess the level of risk to biodiversity. Gap analysis data for California were analyzed with a 'threat index' we developed, based on a combination of roadedness and potential population growth, to prioritize plant communities for conservation action. We also found that the management categories used in GAP were not correlated with trends in bird populations over a period of about a decade as measured by the Breeding Bird Survey. In the second study, we analyzed patterns of richness of rare species with natural and anthopogenic stressors in Washington, Oregon, and California. Hot-spots of rare species were mostly associated in the study area with mild, marine climate but were also associated with large numbers of exotic species. Further study is needed to determine whether these exotic species are actually a threat to rare species where they co-occur or if they are both merely correlated with similar environmental factors. We have also developed a promising new monitoring approach for a satellite-based index of vegetation production. The satellite data are compared to a map of potential production that is modeled from biophysical factors, using areas known to be managed for natural ecological processes as training data. Preliminary results are promising, but more work is needed to determine if the method is robust and can distinguish environmental stress from other sources of deviation.
Tommy D. Dickey: (Link to: http://www.icess.ucsb.edu/~tommy)
The Ocean Physics Laboratory (OPL) focuses on interdisciplinary ocean observations using new technologies. The group has deployed instrumentation in several of the world's oceans. Example locations include: the equatorial Pacific, the central Pacific, near Hawaii, the eastern North Atlantic (near Iceland), the Sargasso Sea, 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 has recently reported results obtained from their measurements in the Arabian Sea where they observed the Northeast and Southwest monsoons and their accompanying seasonal phytoplankton blooms as well as blooms associated with mesoscale eddies. With collaborators from the Woods Hole Oceanographic Institution (WHOI), they have reported what appears to be the most direct evidence of upper ocean primary productivity and carbon flux to great depths. These results are important for understanding the export of carbon to the deep sea via the "biological pump." Related work with collaborators from UCSB, Monterey Bay Aquarium Research Institute (MBARI), WHOI, and the Bermuda Biological Station for Research (BBSR), appears to support the hypothesized importance of eddies for producing enhanced primary productivity (likely associated increased export of photosynthetically fixed organic matter). We have recently reported on the passage of two hurricanes over the Coastal Mixing and Optics mooring site south of Cape Cod in the fall of 1996. These hurricanes produced large sediment resuspension events in an area well known for highly toxic sedimentary materials. The effects of internal solitary waves on optical variability and sediment resuspension are being examined using the CMO data sets as well.
We are now embarking on new technological programs involving robust chemical and bio-optical sensors to be placed on mooring arrays at remote deep-sea sites as well as on autonomous underwater vehicles (AUVs). Field efforts utilizing moorings and/or autonomous underwater vehicles (AUVs) are planned for coastal waters of California and the east coast of the U.S. as well as deep-sea sites in the North Pacific and the Bermuda site. More information on OPL activities may be found on the web site http://www.icess.ucsb.edu/~tommy.
Jeffrey C. Dozier and John M. Melack: (http://www.icess.ucsb.edu/hydro/hydro.html)
Hydrology and Hydrochemistry of Alpine Basins
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.
Thomas Dunne:
Tom Dunne, Leal Mertes, and colleagues of the EOS Amazon project demonstrated in a paper published in the Geological Society of America Bulletin for April, 1998 the surprisingly large exchanges of sediment between the Amazon River and its floodplain. Annual transfers of sediment from the floodplain to the river and from the river to the floodplain were both larger than the annual flux of sediment out of the river to its estuary (1.2 billion tonnes). Four processes of sediment exchange were identified (Bank erosion, bar deposition, diffuse overbank deposition, and channelized overbank deposition) were identified, and techniques for their quantification were developed. The results illustrate the importance of floodplain sedimentation for storing polluted sediments for periods of time that can be predicted quantitatively. It was also found that of the 1.2 billion tonnes per year reaching tidewater only about 75% reach the continental shelf, with the remainder being deposited as a delta plain in the estuary or being transported along the coast of South America by longshore currents.
Catherine H. Gautier: (Link to: http://www.icess.ucsb.edu/esrg.html)
Our work on excess solar radiation absorption over model predictions has taken a new dimension. Besides the modeling component, we have added an observational component from Unmanned Aerospace Vehicle (UAV) and ground spectrometry. Using these measurements we have established the existence of a spectral signature for cloud excess absorption, even in cases where 3-D cloud effects are minimal. This should open the door for a physical understanding of these puzzling effects.
We have also developed a new high spectral resolution (~ 1-2 nm) visible and IR modeling capability for the interpretation of the data from the new generation of satellite sensors soon to be launched on the EOS platform, such as MODIS and AIRS. This model will be the basis of our future cloud studies from space observations. It will also provide us with the necessary high spectral resolution transmission functions for our 3-D cloud modeling studies.
In the area of large-scale air-sea interactions, we completed the development of a capability to accurately compute the main geophysical parameters characterizing the ocean surface and the marine atmosphere, and the exchanges of heat and water that take place at their interface. Monthly mean field can now routinely be produced for the broader scientific community with our algorithms.
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. Primary production of phytoplankton in the Southern Ocean is poorly known compared to temperate marine ecosystems. Consequently remote sensing can play a critical role in studying this large, relatively inaccessible and often inhospitable environment. Under NASA funding we have studied the spatial and temporal variability of phytoplankton production in the Western Antarctic Peninsula (WAP) area, modeled the photoadaptive variability and primary productivity for these waters, and provided a reassessment of primary production of the whole Southern Ocean based upon biogeochemical provinces. As part of the NSF/OPP-funded Palmer Long-Term Ecological Research (LTER) program, aimed at understanding the marine ecology of the Southern Ocean, significant findings include: 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, significant anti-correlation between surface air temperature and sea ice extent, and we have shown that these patterns are coherent with the Southern Oscillation Index (SOI). 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. This has been demonstrated through a collaborative effort that has shown that all climate indicators, both modern instrument and paleo (marine sediment and ice-core), are consistent in showing a warming trend in the WAP in the recent past and especially during the latter half of this century. These data also reveal that ecological responses have occurred over the past 500 years in association with these well-documented climatic changes.
Zhengming Wan:
The MODIS LST Group has developed and delivered Product Generation Executive codes for at-launch standard MODIS LST products based on the generalized split-window LST algorithm (Wan and Dozier, 1996) and the new day/night LST algorithm (Wan and Li, 1997). Two field campaigns with MODIS Airborne Simulator (MAS) flights were conducted in the last year for the validation of the MODIS LST algorithm. Good match (better than 1 degree K) between LST values retrieved from MAS data and those from field measurements enhanced our confidence in the LST algorithm. The day/night LST algorithm was refined by incorporating a simple method for correcting the effect of thin cirrus clouds in dry atmospheric conditions.
Libe Washburn: (link to: http://www.icess.ucsb.edu/iog.html)
A major research accomplishment of our group has been the establishment of an array of 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). Three sites have been established: one at Coal Oil Point near UCSB, a second at the lighthouse at Point Conception, and a third near Refugio State Beach. This radar network led to an exciting new discovery that vast populations of juvenile fishes inhabit a rotating eddy in the Santa Barbara Channel. Based on real-time current observations from the radars, we identified the eddy and directed a research vessel through it. Our colleague, Mary Nishimoto of the Marine Science Institute, conducted net trawls within the eddy that revealed the presence of the high abundance of fishes. Juvenile fish populations within the eddy were 1 to 2 orders of magnitude higher than outside the eddy. We are currently analyzing the data to fully understand the implications of this discovery. In addition to providing valuable data for basic science, the radars will also be used to gather statistics of currents to predict the dispersion of oil in the event of a spill in the Channel.