Landsat has 2 passes thermal data is daytime, but you can also get nighttime passes. Also, don t forget about aerial photography and videography. SPOT is a French satellite, with 20metre multispectral and 10metre panchromatic data. Radar satellite 10m up to 500 m resolution. Airborne data CASI designed for oceanographic work, can be fitted on small aircraft, less than 1metre resolution.
Digital cameras are now high-resolution.
Money is a problem but the data are coming down in price. Remotely sensed data are valuable because they provide historical data particularly valuable in management when you need quick responses, this kind of imagery can help us to look at the past. I ve dabbled in remote sensing, recently more involved with developing tools. It s a very reliable high quality source of data, that has revolutionized what we do. Altimeter is another tool we find useful to find fronts, thermoclines depths, eddies etc.