Time series plots of selected data from Sites A, B, NOAA Buoy 44013, and from coastal stations are presented by year to provide an overview of the observations. Plots were generated using either hour-averaged data, which show fluctuations with periods of hours, or low-pass filtered data, which show fluctuations with periods of a few days. The low-passed filter is designed to remove fluctuations at tidal periods. For plots of current, "profiling current meter" refers to the ADCP; "point current meter" refers to the VMCM (5 mbs and 10 mab) and BASS (1 mab).

Types of Plots:
* Meteorological Observations
* Coastal river streamflow and salinity and temperature
* Low-pass filtered wind stress and point current meter observations
* Low-pass filtered wind stress and ADCP observations, select depths
* Low-pass filtered wind stress and ADCP observations, all depths
* Animation of ADCP
* Pressure Observations
* Surface waves, bottom pressure standard deviation, beam attenuation, bottom current speed, and sediment trapping rate
* Low-passed wind stress, surface waves, and beam attenuation
* Trapping rate of tube sediment traps by year
* Trapping rate of tube and time-series sediment traps
* Monthly mean wind stress and principal ellipse, monthly mean current and principal ellipse (Sites A and B)

Meteorological Observations: Air temperature (degrees C), barometric pressure (mb), wind speed ( m/s), and significant wave height (m)

Coastal river streamflow and salinity and temperature: Stream flow at the Charles, Ipswich, Parker, and Merrimack Rivers (in cubic ft/s), sea surface temperature (in degrees C) from NOAA Buoy 44013, and salinity (in psu) and temperature (in degrees C) at a shallow (Site A, 5 mbs), mid- (Site A, 10 mab; Site B, 10-16 mbs) and deep depth (Site A, 1 mab; Site B, 20-25 mbs). Salinities in the years 1989 - 1996 may be erronously low due to biological fouling of the sensor (see biological fouling). Salinities should increase monotonically from the surface to the bottom.

Low-pass filtered wind stress and point current meter observations: Low-passed wind stress at NOAA Buoy 44013 (dynes/cm²), low-passed current at 5 mbs and 10 mab (from Vector Measuring Current Meters), and at 1 mab (from bottom tripod). Point current meters were only deployed at Site A, and the 5 m VMCM was removed in 1997.

Low-pass filtered wind stress and current observations (from profiling current meter): Low-passed wind stress (from NOAA Buoy 44013) and low-passed currents near the surface (5 mbs), at a mid-depth (Site A, 15 mbs; Site B, 10 mbs) and at the nearest bottom observation (all currents in cm/s).

Low-pass filtered wind stress and current observations (from profiling current meter), all depths: Low-passed wind stress (from NOAA Buoy 44013) and low-passed currents at all depths (all currents in cm/s).

Animation of ADCP data: The ADCP data can also be viewed using the USGS Velocity Profiler Viewer (VPV), a program that creates an animation of the current at all depths measured by the ADCP in 2 m bins.

To view these files:

• Download the free VPV viewer program
• Download the .vel files below (you may need to right click and choose "save target as")
• Right click on one of the saved files and "open with" vpv.exe (if you select the option to always open this type of file with vpv.exe, you can open these files in the future simply by clicking on them below).

Within the animation, right click on the animation for help. The noisy uppermost bin of the ADCP time series has been removed from this visualization.

Pressure observations: Low-passed wind stress (from NOAA Buoy 44013), low-passed bottom pressure (mb), and hour-averaged bottom pressure (mb). The mean has been subtracted from the pressure record prior to plotting.

Surface waves, bottom pressure standard deviation, beam attenuation, bottom current speed, and sediment trapping rate: Hourly significant wave height (from NOAA Buoy 44013) (m), standard deviation of burst bottom pressure (mb, Site A only), beam attenuation (m^-1, Site A only), sediment trapping rate (gm/m²/day) at 9-day intervals from Honjo sediment trap, and current speed 1 mab (cm/s). Biological fouling often degrades light transmission data after several months of deployment. Organisms grow on the transmissometer lenses and gradually block light transmission, which results in a gradual upward drift of the beam attenuation coefficient. This drift occurs more quickly and is more severe at shallower depths. The beam attenuation data plots have not been corrected for biological fouling and should be interpreted with care.

Low-passed wind stress, surface waves, and beam attenuation at 5 mbs, 10 mab, and 1 mab: Low-passed wind stress (dynes/cm²), hourly significant wave height (from NOAA Buoy 44013) (m), and beam attenuation (m^-1) at 5 mbs, 10 mab, and 1 mab at Site A (no instrumentation was deployed at Site B). Biological fouling often degrades light transmission data after several months of deployment. Organisms grow on the transmissometer lenses and gradually block light transmission, which results in a gradual upward drift of the beam attenuation coefficient. This drift occurs more quickly and is more severe at shallower depths. The beam attenuation data plots have not been corrected for biological fouling and should be interpreted with care.

Trapping rate of tube sediment traps by year: Trapping rate of tube traps (gm/ m²/day) as a function of height above the sea floor, grouped by recovery date, and for all traps recovered in each year. Traps were recovered 3 times each year, typically in February, June, and September. Symbols differentiate trapping rate for traps with no poison, and those treated with azide or formalin.

Trapping rate of tube and time-series sediment traps: Trapping rate of tube traps (gm/m²/day) for tube traps deployed 0-2, 3-5, 6-9 and 15-17 m above the sea floor. The trapping rate for the time-series sediment trap is the sum of the individual collections over the deployment interval. Traps were recovered 3 times each year, typically in February, June, and September. The trapping rate is plotted at the recovery date of the trap and indicates the average trapping rate over the deployment interval. Symbols differentiate trapping rate for traps with no poison and for those treated with azide or formalin.

Monthly mean wind stress and principal ellipse, monthly mean current and principal ellipse (calculated from low-passed data at Site A and Site B), and monthly standard deviation of low-passed pressure at Site A: Monthly observed mean current flow (arrows) and the variability (shown as an ellipse centered around the tip of the mean flow arrow) for current at 5 m below the surface at Site A and B. Up is to the north and right is to the east. The mean flow and ellipse were calculated for all months with more than 360 hours of data. Typically the flow originates at the origin of the mean flow arrow and flows toward any point within the current ellipse. The low-pass filter removes the fluctuating tidal currents, and thus the ellipse reflects variability on time scales of a few days and longer due to wind, density, and forcing from the Gulf of Maine.

*Table containing a list of the depth of the deepest ADCP bin for each deployment.

To view files in PDF format, download free copy of Adobe Reader.