# Presentation: 344039

## North Pacific Carbon Cycle Changes

- Projecting Climate change and strategies for detecting climate change

## Background 

- System is not in steady-state with observed decadal changes in both the physical and biological system
- Biological Changes
- HOTS Nitrogen Fixation -> changes in export production and N:P of export organic matter
- Decadal Shifts in Salmon catch
- Water Column Changes
- North Pacific oxygen, AOU and nutrient changes caused by physical and biological changes
- Separating the large decadal changes from global warming changes_x0008_ is a challenge
- Require more sophisticated biophysical models, eg. Eddy resolving with nitrogen fixation

## Observed Changes in the NE Pacific

- Emerson et al, 2001

- 1997 - 1984
- difference

- Section along 150W

## Observed changes in the North Pacific along 27.0 

- Andreev and Watanabe, 2002

- NPI

- WP

- EP

- Sub-arctic

- Decadal signal with East and West Pacific out of phase
- Long-term AOU increase and warming trend

## Simulated North Pacific CO2 Uptake

- Global warming reduces CO2 uptake but the Pacific displays high variability

- Control

- Global Warming

## Simulated North Pacific O2 and N2 Uptake

- Global Warming

- Control

- Weak global warming signal with high variability

## Simulated Annual mean O2 flux variability (mol/m2/yr)

- Oxygen flux variability driven by interannual variability and not by climate change

- Control

- Global Warming

## Simulated North Pacific O2 changes along 27.0  

- Large Decadal variability with observable global warming change
- Increase remineralization of organic matter explains about half the global warming signal

- Global Warming

- Control

- Increase remineralization

## Simulated O2 change between 1990 and 2000

- Global warming change on 27.0
- Distinctive pattern of global warming signal but with a magnitude comparable to the decadal variability signal
- Control run’s decadal variability on 27.0

## Year 2000 change in pCFC-12

- Global warming – Control for year 2000

## New in situ observations

**New in situ observations**

- Complements the repeat sections
- Autonomous profiling of the ocean temperature and salinity   BUTwe need to add biogeochemical measurements

**Notes:**
The ability to measure the ocean autonomously has made regular global observation possible.

Argo is a project to create a global network of profiling floats - 3000 in all - measuring temperature and salinity to 2000 m as the journey to the surface every 10 days. Communications satellites pick up the data and send it around the globe.

Implementation is underway now.  

Complement by research vessels.  

With satellites and models, start of operational oceanography

## Outline

- How are air-sea fluxes affected by the different modes of variability?
- How and why are the distributions of carbon and nutrients changing with time?
- What the requirements for detecting a climate change signal in the North Pacific?
- Variability in air-sea fluxes of carbon and oxygen and CFCs
- Variability in water column inventories of carbon, oxygen, phosphate and CFCs

## Observed Changes 

- Ecosystem Changes
- HOTS Nitrogen Fixation -> changes in export production
- Decadal Shifts in Salmon catch
- Water Column Changes
- Northwest Pacific oxygen, AOU and nutrient changes
- Northeast Pacific oxygen and AOU changes
- Non-steady state system
- Decadal and Climate change impacts

## Observed Changes in the NE Pacific