Chesapeake Bay Bathymetry Data Set
Contributed by Weiqi Lin, Larry Sanford, Steven Suttles, UMCES, HPL
There are many sources for bathymetry data of the Chesapeake. However several have small problems which make their use somewhat problematic in numerical models. Weiqi Lin and Larry Sanford visited the problem when building a wave model for the NOPP Marine Demonstration Project (Lin et al. 1997) (pdf link Waves97.pdf). They rebuilt and hand corrected problems with the data and now make this data available here for download:
Matlab [chesbathy97.mat] -- Arrays of Longitude, Latitude and Depth
>> load chesbathy97.mat >> contourf(longitude,latitude,depth); >> caxis([-50:5:50])
ASCII [nbot.index] -- I, J, Latitude, Longitude, Depth
Fortran readable with:
Do i=1,321 Do j=1,771 Read(1,*) ii,jj,latitude(I), longitude(J), depth(I,J) Enddo Enddo
Matlab Coastline file [chescoastbig2.mat] -- This useful file contains the medium resolution NGDC coastline data. It has been sorted and connected with NaN separating island coasts.
load chescoastbig2.mat plot(coast(:,1),coast(:,2)) figure; clf; hold on l=find(isnan(coast(:,1))); for i=1:length(l)-1 L(i).l=(l(i)+1)-(l(i+1)-1); fill(coast(L(i).l,1),coast(L(i).l,2),'r') end hold off
Bathymetry data were obtained from two primary sources: the National Ocean Service (NOS) of the National Oceanographic and Atmospheric Administration (NOAA), and the Maryland Geological Survey (MGS). Colleagues at Old Dominion University provided digitized NOS mean low water (MLW) bathymetry data for most of Chesapeake Bay, excluding certain portions of the northern Bay. These data are available at 15" by 15" grid resolution. Missing grid points were filled with data digitized directly form NOS navigation charts. Recently measured bathymetry data for the upper Bay obtained from MGS were of much higher resolution (most readings between 3 and 30 meters apart) than the NOS data. The MGS data were grouped into 15" by 15" grid resolution and averaged. These averaged values replaced the NOS values at the corresponding grid points. Data on mean tide levels around the Bay (NOS/NOAA 1996) were interpolated to 15" by 15" grid resolution and added to the MLW bathymetry data set. The final bathymetry data set is the mean water level (in meters) for the Chesapeake Bay.
Weiqi Lin, Lawrence P. Sanford, Brian J. Alleva and David J. Schwab (1997) Surface Wind Wave Modeling in Chesapeake Bay. Ocean Wave Measurement and Analysis Proceedings of the Conference American Society of Civil Engineers. Nov. 3-7, 1997 Virginia Beach, VA.