Selected observations and variables from U.S. Geological Survey water quality stations in south San Francisco Bay. Data include CTD and nutrient measurements.

Format

sfbay is a data frame with 23207 observations (rows) of 12 variables (columns):

[, 1]datedate
[, 2]timetime
[, 3]stnstation code
[, 4]depthmeasurement depth
[, 5]chlchlorophyll a
[, 6]dox.pctdissolved oxygen
[, 7]spmsuspended particulate matter
[, 8]extextinction coefficient
[, 9]salsalinity
[, 10]tempwater temperature
[, 11]noxnitrate + nitrite
[, 12]nhxammonium

sfbayStns is a data frame with 16 observations of 6 variables:

[, 1]sitestation code
[, 2]descriptionstation description
[, 3]latlatitude
[, 4]longlongitude
[, 5]depthMaxmaximum depth, in m
[, 6]distFrom36distance from station 36, in km

sfbayVars is a data frame with 7 observations of 3 variables:

[, 1]variablewater quality variable code
[, 2]descriptiondescription
[, 3]unitsmeasurement units

sfbayChla is a time series matrix (380 months x 16 stations) of average 0-5 m chlorophyll a concentrations calculated from the data in sfbay.

Source

Downloaded from https://sfbay.wr.usgs.gov/water-quality-database/ on 2009-11-17.

Details

The original downloaded dataset was modified by taking a subset of six well-sampled stations and the period 1985--2004. Variable names were also simplified. The data frames sfbayStns and sfbayVars describe the stations and water quality variables in more detail; they were created from information at the same web site. Note that the station numbers in sfbayStns have been prefixed with s to make station codes into legal variable names. sfbayChla was constructed from the entire downloaded sfbay dataset and encompasses the period 1969--2009.

Examples


data(sfbay)
str(sfbay)
#> 'data.frame':	23207 obs. of  12 variables:
#>  $ date : chr  " 1/23/1985" " 1/23/1985" " 1/23/1985" " 1/23/1985" ...
#>  $ time : int  1120 1120 1120 1120 1222 1222 1222 1324 1324 1324 ...
#>  $ stn  : num  21 21 21 21 24 24 24 27 27 27 ...
#>  $ depth: num  1 2 6 12 1 2 9 1 2 12 ...
#>  $ chl  : num  5.6 3.4 3.1 3.4 6.2 5.6 3.3 NA NA NA ...
#>  $ dox  : num  NA NA NA NA NA NA NA NA NA NA ...
#>  $ spm  : int  17 17 18 21 17 18 23 18 19 21 ...
#>  $ ext  : num  1.6 1.6 1.6 1.9 1.6 1.6 2 1.6 1.7 1.9 ...
#>  $ sal  : num  28.1 28.6 28.9 29.4 27.4 ...
#>  $ temp : num  NA NA NA NA NA NA NA NA NA NA ...
#>  $ nox  : num  NA NA NA NA NA NA NA NA NA NA ...
#>  $ nhx  : num  NA NA NA NA NA NA NA NA NA NA ...
str(sfbayStns)
#> 'data.frame':	16 obs. of  6 variables:
#>  $ site       : Factor w/ 16 levels "s21","s22","s23",..: 1 2 3 4 5 6 7 8 9 10 ...
#>  $ description: chr  "Bay Bridge" "Potrero Point" "Hunter's Point" "Candlestick Point" ...
#>  $ lat        : num  37.8 37.8 37.7 37.7 37.7 ...
#>  $ long       : num  -122 -122 -122 -122 -122 ...
#>  $ depthMax   : num  17.4 18 20.1 11 8.8 9.8 13 16.2 14.6 12.8 ...
#>  $ distFrom36 : Factor w/ 16 levels "0","1.66","10.61",..: 14 13 12 11 10 8 7 6 5 4 ...
#>  - attr(*, "units")=List of 2
#>   ..$ depthMax  : chr "m"
#>   ..$ distFrom36: chr "km"
str(sfbayVars)
#> 'data.frame':	8 obs. of  3 variables:
#>  $ variable   : Factor w/ 8 levels "chl","dox","ext",..: 1 2 7 3 6 8 5 4
#>  $ description: chr  "chlorophyll a" "dissolved oxygen" "suspended particulate matter" "extinction coefficient" ...
#>  $ units      : chr  "mg/m3" "mg/L" "mg/L" "1/m" ...
plot(sfbayChla[, 1:10], main = "SF Bay Chl-a")