Abstract. On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia

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The National Aeronautics and Space Administration/ Goddard Space Flight Center's Nimbus Project Office, in collaboration with the NASA/GSFC Space Data and Computing Division, the NASA/GSFC Laboratory for Oceans and the University of Miami/Rosenstiel School of Marine and Atmospheric Science, have undertaken to process all data acquired by the Coastal Zone Color Scanner (CZCS) to Earth‐gridded geophysical values and to provide ready access to data products [Esaias et al., 1986]. An end‐to‐end data system utilizing recent advances in data base management and both digital and analog optical disc storage technologies has been developed to handle the processing, analysis, quality control, archiving and distribution of this data set. A more complete description of this system, which has been fully operational for the past 2 years, is in preparation. The entire Level‐1 data set (see Tables 1, 2) has been copied from magnetic tape to digital optical disc, and all data from the first 32 months (50% of the total scenes acquired, and covering the period November 1978 through June 1981) have been processed to Levels 2 and 3 and are now available for distribution. The remainder of the data set should be completed and released by fall 1989.

Abstract. The Operational Land Imager (OLI) is a multispectral radiometer hosted on the recently launched Landsat8 satellite. OLI includes a suite of relatively narrow spectral bands at 30 m spatial resolution in the visible to shortwave infrared, which makes it a potential tool for ocean color radiometry: measurement of the reflected spectral radiance upwelling from beneath the ocean surface that carries information on the biogeochemical constituents of the upper ocean euphotic zone. To evaluate the potential of OLI to measure ocean color, processing support was implemented in Sea-viewing Wide Field-of-View Sensor (SeaWiFS) Data Analysis System (SeaDAS), which is an open-source software package distributed by NASA for processing, analysis, and display of ocean remote sensing measurements from a variety of spaceborne multispectral radiometers. Here we describe the implementation of OLI processing capabilities within SeaDAS, including support for various methods of atmospheric correction to remove the effects of atmospheric scattering and absorption and retrieve the spectral remote sensing reflectance (Rrs; sr −1 ). The quality of the retrieved Rrs imagery will be assessed, as will the derived water column constituents, such as the concentration of the phytoplankton pigment chlorophyll a.

Climatological mean fields of ocean transparency derived from Secchi depth measurements held by the National Oceanographic Data Center are presented. Clearly evident are the major coastal upwelling regions off Peru, northwest and south Africa as well as the coastally enriched areas globally. The central gyre regions in both North Atlantic and North Pacific waters are separated by a sharp discontinuity in water clarity from the more northern waters; the change in Secchi depth across this subtropical front is equivalent to a difference of ∼1 mg chlorophyll a m−3 over meridional distances of 1000 km. Sufficient data exist in the western Pacific to demonstrate that the front migrates approximately 1000 km seasonally from a northern extreme at ∼28° N in September–November, to a southern extreme at 18° N in March–May. A simple explanation for this feature, which is also clearly evident in recent satellite ocean color images of the the northern ocean basins, is offered in terms of the effective vertical ‘upwelling’ and resulting new production associated with seasonal variations in deep convective mixing.

Mineral dust sources were identified in Sea-viewing Wide Field-of-view Sensor (SeaWiFS) images along the south-west coast of Africa. Up to 150 dust plumes were observed over a 3 year period, and these are linked to sources that are either salt pans or dry river beds in the Namib Desert. This demonstrates that dust supply is maintained by fluvial landforms and associated hydrology. This paper highlights the need to look in more detail at source areas around the globe, as this will further our understanding of dust-production processes.

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Shallow carbonate platforms are a signi cant source of biogenic calcium carbonate (CaCO 3 ) in the marine environment, second in production only to coral reefs. The mechanisms by which platform-derived neritic carbonates are transported to the pelagic water column and deep benthos are signi cant to the geological history of shallow carbonate platforms and the role of neritic carbonates in the marine carbon cycle. Aerial photography and satellite remote sensing observations of the Bahamas Banks and Bermuda indicate that major sediment transport events are caused by strong surface winds associated with storm systems. While this mechanism is not unexpected, these observations provide an initial assessment of the potential ability of remote sensing to detect these events and quantify the oVshore mass transport of neritic carbonate. Strategies for observational monitoring of selected platform environments are described.