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Knit directory: Cant_eMLR/

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library(tidyverse)
library(lubridate)
library(patchwork)

1 Required data

Required are:

  • GLODAPv2.2020
    • cleaned data file
    • horizontal grid of sampling coordinates
  • Cant from GLODAPv2_2016b_MappedClimatologies
  • annual mean atmospheric pCO2
GLODAP <-
  read_csv(
    here::here(
      "data/GLODAPv2_2020/_summarized_data_files",
      "GLODAPv2.2020_clean.csv"
    )
  )

GLODAP_obs_grid <-
  read_csv(
    here::here(
      "data/GLODAPv2_2020/_summarized_data_files",
      "GLODAPv2.2020_clean_obs_grid.csv"
    )
  )

# Cant_clim <-
#   read_csv(here::here("data/GLODAPv1_1/_summarized_files",
#                       "Cant_94.csv"))

Cant_clim <-
  read_csv(
    here::here(
      "data/GLODAPv2_2016b_MappedClimatologies/_summarized_files",
      "Cant.csv"
    )
  )

co2_atm <-
  read_csv(here::here(
    "data/pCO2_atmosphere/_summarized_data_files",
    "co2_atm.csv"
  ))
Cant_clim <- Cant_clim %>%
  rename(cant = Cant)

2 C*

C* serves as a conservative tracer of anthropogenic CO2 uptake. It is derived from measured DIC by removing the impact of

  • organic matter formation and respiration
  • calcification and calcium carbonate dissolution

Contributions of those processes are estimated from phosphate and alkalinity concentrations.

2.1 Stoichiometric ratios

rCP <- 117
rNP <- 16

The stoichiometric nutrient ratios for the production and mineralization of organic matter were set to:

  • C/P: 117
  • N/P: 16

2.2 Calculation

C* is calculated as:

print("Cstar = tco2  + rCP_phosphate  + talk_05  + rNP_phosphate_05")
[1] "Cstar = tco2  + rCP_phosphate  + talk_05  + rNP_phosphate_05"
GLODAP <- GLODAP %>% 
  mutate(rCP_phosphate = -rCP * phosphate,
         talk_05 = -0.5 * talk,
         rNP_phosphate_05 = -0.5 * rNP * phosphate,
         Cstar = tco2  + rCP_phosphate  + talk_05  + rNP_phosphate_05)

rm(rCP, rNP)

3 PO4* calculation

The predictor PO4* was be calculated according to Clement and Gruber (2018), ie based on oxygen. Please note that an errornous equations for PO4* calculation is given in the supplement of Gruber et al (2019), based on nitrate.

GLODAP <- GLODAP %>% 
  mutate(phosphate_star = phosphate + (oxygen / 170)  - 1.95)

4 Reference year adjustment

The reference year adjustment relies on an apriori estimate of Cant at a given location and depth, which is used as a scaling factor for the concurrent change in atmospheric CO2. The underlying assumption is a transient steady state for the oceanic Cant uptake. Here, Cant from the GLODAP mapped Climatology was used.

Note that eq. 6 in Clement and Gruber (2018) misses pCO2 pre-industrial in the denominator. Here we use the equation published in Gruber et al. (2019).

4.1 Merge data sets

4.1.1 GLODAP + Cant

Cant_clim_obs <- left_join(GLODAP_obs_grid, Cant_clim) %>% 
  select(-n)

Cant_clim_obs <- Cant_clim_obs %>%
  group_by(lon, lat) %>% 
  mutate(n = n()) %>% 
  ungroup()

Cant_clim_obs %>%
  filter(n <= 1) %>%
  ggplot(aes(lon,lat)) +
  geom_point(data = GLODAP_obs_grid, aes(lon, lat)) +
  geom_point(col = "red")

rm(Cant_clim, GLODAP_obs_grid)

GLODAP_Cant_obs <- full_join(GLODAP, Cant_clim_obs)

rm(GLODAP, Cant_clim_obs)

GLODAP_Cant_obs <- GLODAP_Cant_obs %>%
  group_by(lon, lat) %>% 
  mutate(n = mean(n, na.rm = TRUE)) %>% 
  ungroup()

The mapped Cant product was merged with GLODAP observation by:

  • using an identical 1x1° horizontal grid
  • linear interpolation of Cant from standard to sampling depth
# GLODAP_Cant_obs <- full_join(GLODAP_Cant_obs, Cant_clim_obs_nr)

GLODAP_Cant_obs <- GLODAP_Cant_obs %>%
  filter(n > 1) %>% 
  group_by(lat, lon) %>%
  arrange(depth) %>%
  mutate(cant_int = approxfun(depth, cant, rule = 2)(depth)) %>%
  ungroup()

# GLODAP_Cant_obs_set <- GLODAP_Cant_obs %>%
#   filter(n_cant == 1) %>% 
#   group_by(lat, lon) %>%
#   arrange(depth) %>%
#   mutate(cant_int = mean(cant, na.rm = TRUE)) %>%
#   ungroup()

# ggplot() +
#   geom_path(
#     data = GLODAP_Cant_obs %>%
#       filter(lat == 48.5, lon == 165.5,!is.na(cant)) %>%
#       arrange(depth),
#     aes(cant, depth, col = "mapped")
#   ) +
#   geom_point(
#     data = GLODAP_Cant_obs %>%
#       filter(lat == 48.5, lon == 165.5,!is.na(cant)) %>%
#       arrange(depth),
#     aes(cant, depth, col = "mapped")
#   ) +
#   geom_point(
#     data = GLODAP_Cant_obs %>%
#       filter(lat == 48.5, lon == 165.5, date == ymd("2018-06-27")),
#     aes(cant_int, depth, col = "interpolated")
#   ) +
#   scale_y_reverse() +
#   scale_color_brewer(palette = "Dark2", name = "") +
#   labs(title = "Cant interpolation to sampling depth - example profile")

# remove cant data at grid cells without observations

GLODAP <- GLODAP_Cant_obs %>%
  filter(!is.na(Cstar)) %>%
  mutate(cant = cant_int) %>%
  select(-cant_int)

rm(GLODAP_Cant_obs)

4.1.2 GLODAP + atm. pCO2

GLODAP observations were merged with mean annual atmospheric pCO2 levels by year.

GLODAP <- left_join(GLODAP, co2_atm)

4.2 Calculate adjustment

GLODAP <- GLODAP %>% 
  group_by(era) %>% 
  mutate(tref = median(year)) %>% 
  ungroup()

tref <- GLODAP %>% 
  group_by(era) %>% 
  summarise(year = median(year)) %>% 
  ungroup()

co2_atm_tref <- right_join(co2_atm, tref) %>% 
  select(-year) %>% 
  rename(pCO2_tref = pCO2)

GLODAP <- full_join(GLODAP, co2_atm_tref)

rm(co2_atm, co2_atm_tref, tref)

GLODAP <- GLODAP %>% 
  mutate(Cstar_tref_delta = 
           ((pCO2 - pCO2_tref) / (pCO2_tref - 280)) * cant,
         Cstar_tref = Cstar - Cstar_tref_delta)

4.3 Control plots

4.3.1 Histogram

GLODAP %>% 
  ggplot(aes(Cstar_tref_delta)) +
  geom_histogram()

4.3.2 Time series

GLODAP %>% 
  sample_n(1e4) %>% 
  ggplot(aes(year, Cstar_tref_delta, col = cant)) +
  geom_point() +
  scale_color_viridis_c() +
  labs(title = "random subsample 1e4")

5 Selected section plots

A selected section is plotted to demonstrate the magnitude of various parameters and corrections relevant to C*.

GLODAP_cruise <- GLODAP %>% 
  filter(cruise %in% parameters$cruises_meridional)
GLODAP_cruise %>%
  arrange(date) %>% 
  ggplot(aes(lon, lat)) +
  geom_raster(data = landmask %>% filter(region == "land"),
              aes(lon, lat), fill = "grey80") +
  geom_path() +
  geom_point() +
  coord_quickmap(expand = 0) +
  #scale_color_viridis_c(trans = "date") +
  labs(title = paste("Cruise year:", mean(GLODAP_cruise$year))) +
  theme(legend.position = "bottom")

lat_section <- 
GLODAP_cruise %>%
  ggplot(aes(lat, depth)) +
  scale_y_reverse() +
  scale_color_viridis_c() +
  theme(legend.position = "bottom")

lat_section +
  geom_point(aes(col = tco2))

lat_section +
  geom_point(aes(col = rCP_phosphate))

lat_section +
  geom_point(aes(col = talk_05))

lat_section +
  geom_point(aes(col = rNP_phosphate_05))

lat_section +
  geom_point(aes(col = Cstar))

lat_section +
  geom_point(aes(col = -Cstar_tref_delta))

rm(lat_section, GLODAP_cruise)

6 Isoneutral slabs

The following boundaries for isoneutral slabs were defined:

  • Atlantic: -, 26, 26.5, 26.75, 27, 27.25, 27.5, 27.75, 27.85, 27.95, 28.05, 28.1, 28.15, 28.2,
  • Indo-Pacific: -, 26, 26.5, 26.75, 27, 27.25, 27.5, 27.75, 27.85, 27.95, 28.05, 28.1,

Continuous neutral densities (gamma) values from GLODAP are grouped into isoneutral slabs.

GLODAP_Atl <- GLODAP %>% 
  filter(basin == "Atlantic") %>% 
  mutate(gamma_slab = cut(gamma, parameters$slabs_Atl))

GLODAP_Ind_Pac <- GLODAP %>% 
  filter(basin == "Indo-Pacific") %>% 
  mutate(gamma_slab = cut(gamma, parameters$slabs_Ind_Pac))

GLODAP <- bind_rows(GLODAP_Atl, GLODAP_Ind_Pac)

rm(GLODAP_Atl, GLODAP_Ind_Pac)
GLODAP_cruise <- GLODAP %>% 
  filter(cruise %in% parameters$cruises_meridional)

lat_section <- 
GLODAP_cruise %>%
  ggplot(aes(lat, depth)) +
  scale_y_reverse() +
  theme(legend.position = "bottom")

lat_section +
  geom_point(aes(col = gamma_slab)) +
  scale_color_viridis_d()

rm(lat_section, GLODAP_cruise)
GLODAP_cruise <- GLODAP %>% 
  filter(cruise %in% parameters$cruises_meridional)

library(oce)
library(gsw)
# calculate pressure from depth

GLODAP_cruise <- GLODAP_cruise %>% 
  mutate(CTDPRS = gsw_p_from_z(-depth,
                               lat))

GLODAP_cruise <- GLODAP_cruise %>% 
  mutate(THETA = swTheta(salinity = sal,
                         temperature = tem,
                         pressure = CTDPRS,
                         referencePressure = 0,
                         longitude = lon-180,
                         latitude = lat))

GLODAP_cruise <- GLODAP_cruise %>% 
  rename(LATITUDE = lat,
         LONGITUDE = lon,
         SALNTY = sal,
         gamma_provided = gamma)

library(reticulate)
source_python(here::here("code/python_scripts",
                         "Gamma_GLODAP_python.py"))

GLODAP_cruise <- calculate_gamma(GLODAP_cruise)

GLODAP_cruise <- GLODAP_cruise %>% 
  mutate(gamma_delta = gamma_provided - GAMMA)

lat_section <- 
GLODAP_cruise %>%
  ggplot(aes(LATITUDE, CTDPRS)) +
  scale_y_reverse() +
  theme(legend.position = "bottom")

lat_section +
  geom_point(aes(col = gamma_delta)) +
  scale_color_viridis_c()

GLODAP_cruise %>% 
  ggplot(aes(gamma_delta))+
  geom_histogram()

rm(lat_section, GLODAP_cruise, cruises_meridional)

7 Observations coverage

GLODAP <- GLODAP %>% 
  mutate(era = factor(era, c("JGOFS_WOCE", "GO_SHIP", "new_era"))) %>%
  mutate(gamma_slab = factor(gamma_slab), 
         gamma_slab = factor(gamma_slab, levels = rev(levels(gamma_slab))))

GLODAP %>% 
  filter(basin == "Atlantic") %>% 
  ggplot(aes(lat, gamma_slab)) +
  geom_bin2d(binwidth = 5) +
  scale_fill_viridis_c(option = "magma", direction = -1, trans = "log10",
                       name = "log10(n)") +
  scale_x_continuous(breaks = seq(-100,100,20)) +
  facet_grid(era~basin)

GLODAP %>% 
  filter(basin == "Indo-Pacific") %>% 
  ggplot(aes(lat, gamma_slab)) +
  geom_bin2d(binwidth = 5) +
  scale_fill_viridis_c(option = "magma", direction = -1, trans = "log10",
                       name = "log10(n)") +
  scale_x_continuous(breaks = seq(-100,100,20)) +
  facet_grid(era~basin)

8 Individual cruise sections

Zonal and meridional section plots are produce for each cruise individually and can be downloaded here.

cruises <- GLODAP %>% 
  group_by(cruise) %>% 
  summarise(date_mean = mean(date, na.rm = TRUE),
            n = n()) %>% 
  ungroup() %>% 
  arrange(date_mean)

GLODAP <- full_join(GLODAP, cruises)

n <- 0
for (i_cruise in unique(cruises$cruise)) {

#i_cruise <- unique(cruises$cruise)[1]
n <- n+1
print(n)  
  
GLODAP_cruise <- GLODAP %>%
  filter(cruise == i_cruise) %>% 
  arrange(date)

cruises_cruise <- cruises %>%
  filter(cruise == i_cruise)
  
map <- GLODAP_cruise %>%
  ggplot(aes(lon, lat)) +
  geom_raster(data = landmask %>% filter(region == "land"),
              aes(lon, lat), fill = "grey80") +
  geom_point(aes(col=date)) +
  coord_quickmap(expand = FALSE) +
  scale_color_viridis_c(trans = "date") +
  labs(title = paste("Mean date:", cruises_cruise$date_mean,
                     "| cruise:", cruises_cruise$cruise,
                     "| n(samples):", cruises_cruise$n))


lon_section <- GLODAP_cruise %>%
  ggplot(aes(lon, depth)) +
  scale_y_reverse() +
  scale_color_viridis_c()

lon_tco2 <- lon_section+
  geom_point(aes(col=tco2))

lon_talk <- lon_section+
  geom_point(aes(col=talk))

lon_phosphate <- lon_section+
  geom_point(aes(col=phosphate))

lon_oxygen <- lon_section+
  geom_point(aes(col=oxygen))

lon_aou <- lon_section+
  geom_point(aes(col=aou))

lon_phosphate_star <- lon_section+
  geom_point(aes(col=phosphate_star))

lon_nitrate <- lon_section+
  geom_point(aes(col=nitrate))

lon_Cstar <- lon_section+
  geom_point(aes(col=Cstar))


lat_section <- GLODAP_cruise %>%
  ggplot(aes(lat, depth)) +
  scale_y_reverse() +
  scale_color_viridis_c()

lat_tco2 <- lat_section+
  geom_point(aes(col=tco2))

lat_talk <- lat_section+
  geom_point(aes(col=talk))

lat_phosphate <- lat_section+
  geom_point(aes(col=phosphate))

lat_oxygen <- lat_section+
  geom_point(aes(col=oxygen))

lat_aou <- lat_section+
  geom_point(aes(col=aou))

lat_phosphate_star <- lat_section+
  geom_point(aes(col=phosphate_star))

lat_nitrate <- lat_section+
  geom_point(aes(col=nitrate))

lat_Cstar <- lat_section+
  geom_point(aes(col=Cstar))

hist_tco2 <- GLODAP_cruise %>%
  ggplot(aes(tco2)) +
  geom_histogram()

hist_talk <- GLODAP_cruise %>%
  ggplot(aes(talk)) +
  geom_histogram()

hist_phosphate <- GLODAP_cruise %>%
  ggplot(aes(phosphate)) +
  geom_histogram()

hist_oxygen <- GLODAP_cruise %>%
  ggplot(aes(oxygen)) +
  geom_histogram()

hist_aou <- GLODAP_cruise %>%
  ggplot(aes(aou)) +
  geom_histogram()

hist_phosphate_star <- GLODAP_cruise %>%
  ggplot(aes(phosphate_star)) +
  geom_histogram()

hist_nitrate <- GLODAP_cruise %>%
  ggplot(aes(nitrate)) +
  geom_histogram()

hist_Cstar <- GLODAP_cruise %>%
  ggplot(aes(Cstar)) +
  geom_histogram()

(map /
    ((hist_tco2 / hist_talk / hist_phosphate / hist_Cstar) |
       (hist_oxygen / hist_phosphate_star / hist_nitrate / hist_aou)
    )) |
  ((lat_tco2 / lat_talk / lat_phosphate / lat_oxygen / lat_aou / lat_phosphate_star / lat_nitrate / lat_Cstar) |
     (lon_tco2 / lon_talk / lon_phosphate / lon_oxygen /  lon_aou /lon_phosphate_star / lon_nitrate / lon_Cstar))    

ggsave(here::here("output/figure/eMLR/data_preparation/all_cruises_clean",
                  paste("GLODAP_cruise_date",
                        cruises_cruise$date_mean,
                        "n",
                        cruises_cruise$n,
                        "cruise",
                        cruises_cruise$cruise,
                        ".png",
                        sep = "_")),
                  width = 20, height = 12)

rm(map,
   lon_section, lat_section,
   lat_tco2, lat_talk, lat_phosphate, lon_tco2, lon_talk, lon_phosphate,
   GLODAP_cruise, cruises_cruise)

}

9 Write file

GLODAP %>% write_csv(here::here("data/GLODAPv2_2020/_summarized_data_files",
                                "GLODAP_MLR_fitting_ready.csv"))

10 Open tasks

11 Open questions


sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18363)

Matrix products: default

locale:
[1] LC_COLLATE=English_Germany.1252  LC_CTYPE=English_Germany.1252   
[3] LC_MONETARY=English_Germany.1252 LC_NUMERIC=C                    
[5] LC_TIME=English_Germany.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] patchwork_1.0.1 lubridate_1.7.9 forcats_0.5.0   stringr_1.4.0  
 [5] dplyr_1.0.0     purrr_0.3.4     readr_1.3.1     tidyr_1.1.0    
 [9] tibble_3.0.3    ggplot2_3.3.2   tidyverse_1.3.0 workflowr_1.6.2

loaded via a namespace (and not attached):
 [1] tidyselect_1.1.0  xfun_0.16         haven_2.3.1       colorspace_1.4-1 
 [5] vctrs_0.3.2       generics_0.0.2    viridisLite_0.3.0 htmltools_0.5.0  
 [9] yaml_2.2.1        blob_1.2.1        rlang_0.4.7       later_1.1.0.1    
[13] pillar_1.4.6      withr_2.2.0       glue_1.4.1        DBI_1.1.0        
[17] dbplyr_1.4.4      modelr_0.1.8      readxl_1.3.1      lifecycle_0.2.0  
[21] munsell_0.5.0     gtable_0.3.0      cellranger_1.1.0  rvest_0.3.6      
[25] evaluate_0.14     labeling_0.3      knitr_1.29        httpuv_1.5.4     
[29] fansi_0.4.1       broom_0.7.0       Rcpp_1.0.5        promises_1.1.1   
[33] backports_1.1.8   scales_1.1.1      jsonlite_1.7.0    farver_2.0.3     
[37] fs_1.4.2          hms_0.5.3         digest_0.6.25     stringi_1.4.6    
[41] rprojroot_1.3-2   grid_4.0.2        here_0.1          cli_2.0.2        
[45] tools_4.0.2       magrittr_1.5      crayon_1.3.4      whisker_0.4      
[49] pkgconfig_2.0.3   ellipsis_0.3.1    xml2_1.3.2        reprex_0.3.0     
[53] assertthat_0.2.1  rmarkdown_2.3     httr_1.4.2        rstudioapi_0.11  
[57] R6_2.4.1          git2r_0.27.1      compiler_4.0.2