Last updated: 2020-08-19

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Knit directory: Cant_eMLR/

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Rmd 94f9375 jens-daniel-mueller 2020-08-19 split emlr into data preparation, assumption testing, and model fitting
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Rmd 77b2dc1 jens-daniel-mueller 2020-08-19 split emlr into data preparation, assumption testing, and model fitting

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

Currently, the predictor PO4* is calculated according to Clement and Gruber (2018), ie based on oxygen rather than nitrate, as claimed in Gruber et al (2019).

GLODAP <- GLODAP %>% 
  mutate(phosphate_star_oxy_corr = (oxygen / 170)  - 1.95,
         phosphate_star_oxy = phosphate + phosphate_star_oxy_corr)
GLODAP <- GLODAP %>% 
  mutate(phosphate_star_nit_corr = - nitrate/16  + 2.9,
         phosphate_star_nit = phosphate + phosphate_star_nit_corr)

3.1 Comparison of approaches

GLODAP %>% 
  ggplot(aes(oxygen,
             nitrate)) +
  geom_bin2d() +
  scale_fill_viridis_c() +
  facet_wrap(~basin)

GLODAP %>% 
  ggplot(aes(phosphate,
             nitrate)) +
  geom_bin2d() +
  scale_fill_viridis_c() +
  facet_wrap(~basin)

GLODAP %>% 
  ggplot(aes(phosphate,
             oxygen)) +
  geom_bin2d() +
  scale_fill_viridis_c() +
  facet_wrap(~basin)

GLODAP %>% 
  ggplot(aes(phosphate_star_oxy_corr,
             phosphate_star_nit_corr)) +
  geom_bin2d() +
  scale_fill_viridis_c() +
  facet_wrap(~basin)

GLODAP %>% 
  ggplot(aes(phosphate_star_oxy, phosphate_star_nit)) +
  geom_bin2d() +
  scale_fill_viridis_c() +
  facet_wrap(~basin)

GLODAP <- GLODAP %>% 
  select(-c(
    phosphate_star_nit,
    phosphate_star_oxy_corr)) %>% 
  rename(phosphate_star = phosphate_star_oxy)

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 <- Cant_clim %>% 
  drop_na()

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

# Cant_clim_obs_nr <- Cant_clim_obs %>%
#   group_by(lon, lat) %>%
#   summarise(n_cant = 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)

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_cant > 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$cruises_meridional)
GLODAP_cruise %>%
  arrange(date) %>% 
  ggplot(aes(lon, lat)) +
  geom_raster(data = landmask %>% filter(region == "land"),
              aes(lon, lat), fill = "grey80") +
  geom_path() +
  geom_point(aes(col = date)) +
  coord_quickmap(expand = 0) +
  scale_color_viridis_c(trans = "date") +
  labs(title = paste("Cruise year:", mean(GLODAP_cruise$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)
GLODAP_cruise <- GLODAP_cruise %>% 
  mutate(THETA = swTheta(salinity = sal,
                         temperature = tem,
                         pressure = depth,
                         referencePressure = 0,
                         longitude = lon-180,
                         latitude = lat))

GLODAP_cruise <- GLODAP_cruise %>% 
  rename(LATITUDE = lat,
         LONGITUDE = lon,
         SALNTY = sal,
         CTDPRS = depth,
         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 Write file

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

9 Open tasks

10 Open questions

  • Which PO4* calculation is “correct”?

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] Rcpp_1.0.5         here_0.1           assertthat_0.2.1   rprojroot_1.3-2   
 [5] digest_0.6.25      R6_2.4.1           cellranger_1.1.0   backports_1.1.8   
 [9] reprex_0.3.0       evaluate_0.14      httr_1.4.2         pillar_1.4.6      
[13] rlang_0.4.7        readxl_1.3.1       rstudioapi_0.11    whisker_0.4       
[17] blob_1.2.1         rmarkdown_2.3      labeling_0.3       munsell_0.5.0     
[21] broom_0.7.0        compiler_4.0.2     httpuv_1.5.4       modelr_0.1.8      
[25] xfun_0.16          pkgconfig_2.0.3    htmltools_0.5.0    tidyselect_1.1.0  
[29] fansi_0.4.1        viridisLite_0.3.0  crayon_1.3.4       dbplyr_1.4.4      
[33] withr_2.2.0        later_1.1.0.1      grid_4.0.2         jsonlite_1.7.0    
[37] gtable_0.3.0       lifecycle_0.2.0    DBI_1.1.0          git2r_0.27.1      
[41] magrittr_1.5       scales_1.1.1       cli_2.0.2          stringi_1.4.6     
[45] farver_2.0.3       fs_1.4.2           promises_1.1.1     xml2_1.3.2        
[49] ellipsis_0.3.1     generics_0.0.2     vctrs_0.3.2        RColorBrewer_1.1-2
[53] tools_4.0.2        glue_1.4.1         hms_0.5.3          yaml_2.2.1        
[57] colorspace_1.4-1   rvest_0.3.6        knitr_1.29         haven_2.3.1