buoy {ocedata}

Measurements made at a buoy off Halifax

Description

buoy is a data frame holding hourly observations made between March 3 and April 18 of 2014, at the Environment Canada 3-metre discus buoy situated at (44.502N 63.403W) near Halifax Harbour.

Usage

data(buoy, package="ocedata")

Details

The contents are as follows; other items in the original data file are ignored.

• time: time of observation, in POSIXct() format.

• wind: wind speed in m/s.

• direction: direction from which the wind is blowing, measured in degrees clockwise of true North.

• gust: gust speed in m/s.

• height: wave height in metres.

• period: wave period in seconds.

• pa: atmospheric pressure in kPa.

• Ta: air temperature in degC.

• Tw: water temperature in degC. The data were downloaded as a file named ⁠44258.txt⁠ in April 2014 from Reference 1, and made into a data frame. See References 2 and 3 for information on the data in such buoys, and 4 for more on this particular buoy.

The code to create the dataset is given below.

d <- read.table("44258.txt", stringsAsFactors=FALSE, skip=2)
t <- ISOdatetime(d[,1], d[,2], d[,3], d[,4], d[,5], 0, tz="UTC")
o <- order(t)
# handle missing data
d[d == "MM"] <- NA
# put oldest first
t <- t[o]
d <- d[o,]
direction <- as.numeric(d[,6])
wind <- as.numeric(d[,7])
gust <- as.numeric(d[,8])[o]
height <- as.numeric(d[,9])
period <- as.numeric(d[,10])
pa <- as.numeric(d[,13])
Ta <- as.numeric(d[,14])
Tw <- as.numeric(d[,15])

References

1. https://www.ndbc.noaa.gov/data/realtime2/

2. https://www.ndbc.noaa.gov/NDBCHandbookofAutomatedDataQualityControl2009.pdf

3. https://www.ndbc.noaa.gov/measdes.shtml

4. ⁠https://www.ndbc.noaa.gov/station_page.php?station=44258⁠ (link seen to time out on March 13, 2022).

Examples

data(buoy, package="ocedata")
plot(buoy$time, buoy$wind, ylab="Wind Speed [m/s]")
plot(buoy$time, buoy$height, ylab="Wave height [m]")
plot(buoy$time, buoy$period, ylab="Wave period [s]")