CE/NR797 Lab Report: Water and wind
circulation
[Prepared
by R. Fortner for ¡§Digital and
Field Techniques for Coastal Environment Studies,¡¨ 7/02]
Objective
:
To develop a general model of the relationship between physical movements
and characteristics of lake components around Gibraltar Island, for purposes
of prediction and to facilitate research. In general, we will try to
identify how wind speed and direction are related to surface and internal
current speed and direction, and how these movements could affect sediment
transport and Stone Lab research protocols.
Methodology:
Please report on the methods used for
data collection, including the following
Instruments and procedure used to
measure the variables of
- wind speed and direction
- current speed and direction
- water transparency
- station location
Sources of error in measurements
Location (url) and source of data used in GLFS
Results:
A. Sampling locations. On a map that
includes Put-in-Bay, Gibraltar and Middle Bass Islands, plot the locations
of data collection over the period of the lab. For this section we are most
interested in the range of geographic area covered by measurements rather
than the specific dates of collection at the points. Your figure caption
should include the starting and ending dates of data collection.
B. Wind. Develop a wind rose for the
Bay and one for the Buoy area to illustrate the speed and direction of wind
in July 2002.
C. Wind and surface water. Using your
spreadsheet, compare the speed of surface current with speed of wind for the
entire period, and plot surface current direction against wind direction
(all points with data available on the four variables). Attach graphs
clearly labeled for the variables and the analysis intended.
D. Water level. Use the limnology
class data, the 797 periodic reports, and Coastwatch to get data on lake
water levels at Marblehead at the general times of your wind readings. Use
In Situ data, Water Level, Preliminary Current Water Level data. Add the
data from the most complete source to your spreadsheet and analyze for
relationships. Show graphically how/whether lake level was related to wind
speed or direction or both during your study period.
E. Surface and subsurface water.
Demonstrate with your data the relationship between surface and subsurface
currents (direction and speed for the dates possible).
F. Water transparency. Secchi depths
are included prominently in the water chemistry lab report. In addition to
the role in primary productivity, this variable relates to the ability of
researchers at Stone Lab to complete their research protocols. Murky water
and moving sediment, especially accompanied by rough water, makes some
research more difficult. Review the secchi data and determine if the
measures are related to wind speed or subsurface current in either the bay
or lake.
Analysis and
applications
1. Summary of variable relationships.
In simple statements describe the relationships between the variables you
measured. This may be in chart or list form as you prefer.
2. Relationship to on-line reports.
For any 3 days of sampling, examine the GLFS data on Integrated Currents (V)
and Wind (W) and determine the extent to which local measures match the
model. If you magnify the GLFS image you may be able to get greater
definition of the region you have studied. For a recent period of 2 days of
sampling, determine how closely the MAROBS South Bass buoy data match your
wind direction and speed data. If the SBI buoy is not on your map of data
stations, add it at Latitude : 41.64 degrees, Longitude : 82.84 degrees.
Discuss the value of field observations used concurrently with on-line data.
3. General. Describe the sources of
error in your data. Under ideal conditions (dependable equipment and safe
boating conditions) what could the data collectors do to increase confidence
in the data (not statistical confidence but personal confidence related to
data integrity and reproducibility).
4. Research applications. Numerous
researchers need to use lake data in their work and must collect the data on
or under the water. Attached is a list of research projects in progress at
the Lab this summer. For two projects that you choose, tell briefly how data
on some variables you measured could be used in the work, either as a
predictive dataset, identifying constraints to sampling, a needed piece of
information, or other use.