San Francisco Bay water quality data

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]`	`date`	date
`[, 2]`	`time`	time
`[, 3]`	`stn`	station code
`[, 4]`	`depth`	measurement depth
`[, 5]`	`chl`	chlorophyll a
`[, 6]`	`dox.pct`	dissolved oxygen
`[, 7]`	`spm`	suspended particulate matter
`[, 8]`	`ext`	extinction coefficient
`[, 9]`	`sal`	salinity
`[, 10]`	`temp`	water temperature
`[, 11]`	`nox`	nitrate + nitrite
`[, 12]`	`nhx`	ammonium

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

`[, 1]`	`site`	station code
`[, 2]`	`description`	station description
`[, 3]`	`lat`	latitude
`[, 4]`	`long`	longitude
`[, 5]`	`depthMax`	maximum depth, in m
`[, 6]`	`distFrom36`	distance from station 36, in km

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

`[, 1]`	`variable`	water quality variable code
`[, 2]`	`description`	description
`[, 3]`	`units`	measurement 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")