Estimating Primary Productivity with WIM/WAM

Transcription

1 Estimating Primary Productivity with WIM/WAM Please see \Course\4\Tutorial_Primary_Productivity.pdf on DVD or Ocean primary production (PP) is a crucial component of the Earth s biogeochemical cycles of carbon and other major chemical elements. Net primary production (NPP, g C m -2 d -1 ), i.e. total primary production minus the losses due to respiration of the phytoplankton, provides the upper bound for production at higher trophic levels. In situ measurement of PP or NPP is extremely time-consuming and not representative of a larger area due to high spatial and temporal variability. Obtaining estimates of PP at regional and global scales are therefore very difficult to make without the quasi-synoptic view provided by satellite data or numerical models. In this tutorial we try several ways of estimating NPP with WIM/WAM.

2 Primary Production Measurement Biomass (Chl or Carbon) Photos by J. Ishizaka In situ Method Rate of Carbon Fixed ( 14 C or 13 C Incubation Method) Simulated In Situ Method

3 Typical Satellite Primary Production Model, e.g. Behrenfeld-Falkowski, 1997 Other NPP models may use different input, e.g. CbPM uses bbb, b, K490, PAR, GSM-Chl, GSM-Chl-a, MLD MLD Modified from J. Ishizaka

4 Depth VGPM (Vertically Generalized Production Model) Behrenfeld & Falkowski (1997) PAR IPP = P B opt f[par(0)] DL Z eu Chl.a(0) PP/Chl.a Euphotic Zone (Z eu ) Chl.a(0) P B opt Behrenfeld&Falkowski(1997) P b opt (7th Order Polynomial of SST) Day Length (DL) Surface Z eu Integrated Chl.a J. Ishizaka IPP IPP : Integrated Primary Production

5 Modified Behrenfeld and Falkowski (1997) Two-Phytoplankton-Community Model (Kameda and Ishizaka, JO-2005) PP eu = P B opt [E 0 / (E )] Z eu C z0 D irr P B opt = g (SST) B&F 7 th order polynomial P B opt = g (SST, CHL) K&I CHL = CHL S + CHL L Prod = Prod S CHL S + Prod L CHL L J. Ishizaka

6 Maximum Photosynthetic Rate per Chl-a (P B opt) Temp. Dependent (Behrenfeld and Falkowski, 1997) Temp. and Chl. Dependent (Kameda and Ishizaka, 2005)

7 GLI (April-June 2004) Chl-a SST PAR - Primary Production

8 Validating Primary Productivity measurements Please see \Course\4\Tutorial_Primary_Productivity.pdf on DVD or Can use wam_match with NPP images but it s an overkill to create global NPP datasets to validate some point measurements Copy \Sat folder from DVD to C:\ Need input data: in situ NPP file qprodopoint_2007.csv in\sat\merged\l4 with Lon, Lat, Date, Time, NPP (this is CalCOFI 2007 simulated on-deck NPP ) List file list_calc_npp_vgpm_l3_merged.txt that specifies directories of satellite data and the in situ NPP file Satellite data corresponding to the list file

9 Validating Primary Productivity cont. If you have not done it yet, create Merged Daily Chl-a from corresponding SeaWiFS and MODISA daily datasets. Daily datasets typically miss lots of data due to clouds and swath coverage. As test, we can use Monthly data. Use data in SeaWiFS\L3\Daily\CHL_9 and MODISA\L3\Daily\CHL_9 or SeaWiFS\L3\Monthly\CHL_9 and MODISA\L3\Monthly\CHL_9 as input cd C:\Sat wam_composite_2sensors SeaWiFS\L3\Monthly\CHL_9\S2007*.hdf MODISA\L3\Monthly\CHL_9\A2007*.hdf mkdir Merged\L3\Monthly\CHL_9 move M*.hdf Merged\L3\Monthly\CHL_9 ************************** wam_composite_2sensors SeaWiFS\L3\Daily\CHL_9\S2007*.hdf MODISA\L3\Daily\CHL_9\A2007*.hdf mkdir Merged\L3\Daily\CHL_9 move *.hdf Merged\L3\Daily\CHL_9

10 Validating Primary Productivity cont. Contents of the list file (explain the naming of the file!) list_calcofi_vgpm_l3_2007_swfaqu1_swf1_mod8.txt : # 1 - Chl C:\Sat\Merged\L3\Daily\CHL_9,?2007*9km.hdf # 2 - PAR C:\Sat\SeaWiFS\L3\Daily\PAR_9,S2007*9km.hdf # 3 - SST C:\Sat\Merged\L3\8day\SST_9,M2007*.hdf # 4 - Points C:\Sat\Merged\L4\qProdoPoint_2007.csv # means comment Each line has path and matching filename pattern separated by comma

11 Validating Primary Productivity, cont. Open command prompt, cd to C:\Sat\Merged\L4 We will use: Aqua-SeaWiFS merged daily Chl-a - merged data has better coverage! SeaWiFS daily PAR - PAR can change rapidly due to clouds! Merged Terra-Aqua 8-day SST will use 8-day to improve coverage as SST influence is rather weak Run: wam_npp_point list_calc_npp_vgpm_l3_merged.txt VGPM Explain the number of files used: 364, 355, 46, 1 Explain the output to screen Out file name will be list file name + _out.csv Rename the output file *.txt_out.csv to*.vgpm.csv

12 Log 10 of NPP-Sat Validating Primary Productivity cont. Load output file into Excel, create new variables: LogInsitu and LogSat as LOG() of respective column Make plots of NPP-Sat versus NPP-in situ like in Tutorial y = x R² = Log 10 of NPP-in situ, mg C m-2 d-1 Load output into wam_match, try to eliminate a few outliers You can try other NPP models; type wam_npp_point without arguments to see all available options

13 New task.

14 Calculating Primary Productivity (images!) Calculating Monthly NPP data; can be global or local at any resolution depending on the component satellite data Earlier versions used exact list of images; now using a list file that specifies only the paths and patterns of component data 1 st component image (e.g. Chl-a) is the primary image that specifies the outpout resolution, wam_npp itself will find the best corresponding matching images in time, will remap if necessary Contents of a sample list file list_calc_npp_vgpm_l3_merged.txt : # path for Chl files, matching pattern #C:\Sat\Merged\L3\Monthly\CHL_9,*CHLO*.hdf # path for PAR files, matching pattern C:\Sat\SeaWiFS\L3\Month\PAR_9,S*PAR*.hdf # path for SST files, matching pattern C:\Sat\Merged\L3\Month\SST_9,M*.hdf # means comment Each line has path and matching filename pattern separated by comma

15 Calculating Primary Productivity, cont. Open command prompt, cd C:\Sat\L4, run: wam_npp list_calc_npp_vgpm_l3_merged.txt This will create 12 monthly NPP images of 2007 using VGPM model Type wam_npp without arguments to see available options Explain how to calculate NPP, based on OCTS Chl-a, SeaWiFS PAR and AVHRR Pathfinder SST