Lab 1: Bathymetry and position data

 

The goal of this lab is to familiarize you with using position and bathymetry data (2-D and 3-D) in MatLab, and to get a feel for working with "real" data that will be similar (if not identical) to that collected during the cruise. 

 

 

The functions necessary to complete this assignment are:  
LOAD            loads data files into MatLab 
PLOT             Plots 2-D (X-Y) data 
CONTOUR   Contour plot of 3-D data in a flat (2-D) representation 
CLABEL        Labels contours generated using CONTOUR function 
MESH            Plots a 3-D mesh surface (3-D spatial representation)
LEGEND       add legend information for plot contents
DISTANCE    calculates the distance (degrees) between Lat/Lon points.

DEG2KM        converts degrees of arc to kilometers of distance on a circle

VIEW              changes to viewing aspect of a 3-D plot (azimuth/elevation angles)
PLOT3            Plots 3-D (X-Y-Z) data
TRACK2 or GCWAYPTS        (Mapping toolbox) extracts track points between 2 positions.
INTERP1,  INTERP2        Interpolates for Zi at corresponding Xi,Yi values, given gridded input data (X, Y, and Z).

 

UDASREAD Custom function to extract ship's Underway Data Acquisition System (UDAS) position & information

SEABIRDREAD_AUG10  Custom function to extract CTD cast data from Aug2010 Microcat data

Project questions:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1) Generate a 2-D contour plot of the Central California bathymetry
(contained in ccal250.mat), with contour intervals from the surface (0m), every 500m to
maximum depth. Label the contour intervals and axes.

MatLab functions: load, contour, clabel, xlabel, ylabel, title

Required data files: ccal250.mat (bathymetry data)

 

2)  Plot a 3-D mesh surface of the Central California bathymetry,
with an azimuthal viewing angle of -50, and an elevation angle of 75.
Label axes and title appropriately.

MatLab functions: load, mesh, view, xlabel, ylabel, title, colorbar

Required data files: ccal250.mat (bathymetry data)

 

3)  Plot the ship track (see udasread.m), EMATT track, AcousondeTM mooring and CTD / sediment grab positions (manually pull from cruise log) for the provided experiment data, including the bathymetry contours (every 10m).  Label axes and provide a legend to identify the ship & EMATT track line(s), CTD & grab locations.

 

Custom functions (provided): udasread.m, EMATT_track.m

MatLab functions:  contour, hold, plot, legend, axis, udasread

Mapping toolbox functions: distance, almanac

Lab data files : OC4270_080610.LOG (cruise log text), jhmudas_201086.txt (ship track), ccal250.mat (bathymetry), DelMonte_RPS1.csv (EMATT geometry data)

 

 

 

4) Generate range & bearing time series between the AcousondeTM mooring location (from log) and the projected EMATT position, and plot (see EMATT_track.m if you need an example). Repeat using these same functions for the ship position data extracted above.

 

Custom functions (provided): udasread.m, EMATT_track.m

MatLab functions:  plot, axis, interp1, xlabel, ylabel, title

Mapping toolbox functions: distance, almanac

Lab data files : OC4270_080610.LOG (cruise log text), jhmudas_201086.txt (ship track), DelMonte_RPS1.csv (EMATT geometry data)

 

Example for distance usage (mapping toolbox needed):

[rng,az]=distance(lat1,lon1,lat2,lon2,almanac('Earth','wgs84'));

5) Environmental data for model inputs.

Extract the bathymetry between the AcousondeTM mooring location and the 80m CTD cast taken at 19:42 (36° 39.808' N, 121° 54.588' W).

 

Plot depth (m) vs. range (km) along this track as a 2-D plot.

 

Plot sound velocity profiles from CTD casts contained from the cruise data.

 

Custom functions (provided): seabirdread_Aug10.m

MatLab functions (Mapping Toolbox): gcwaypts, interp2, distance, almanac

Required data files: OC4270_Aug10.asc, ccal250.mat (bathymetry data)

 

NOTE: CTD casts end before the bottom depth (for equipment safety). For many ocean models, this data is the only defining element for the water column, and therefore information must be extrapolated down to the bottom depth or the model will see the disparity between the bottom of the ocean and the bathymetry.

 

Rev. 7/27/11