2014-15 Call for Datafor Nitrogen and Sulphur

Critical Load Functions(N & S CLFs)

Coordination Centre for Effects (CCE)of the

ICP Modelling & Mapping (ICP M&M)of the

Working Group on Effects (WGE)

J-P Hettelingh, M Posch, J Slootweg

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Reasons for a Call for Data:

1. Change in EMEP deposition grid

2. Requests for update by some NFCs (e.g. due to improved national knowledge)

3. New (policy-driven) emphasis on biodiversity

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Ad 1:EMEP N and S depositions now on a longitude-latitude grid:Grid cells of size ½⁰ × ¼⁰, i.e. ~28 km (at 60⁰N) × ~28km

the “28 km grid”

Ad 2:Inter alia, opportunity to provide (better) CLs for Natura2000 (and other protected) areas

Size of grid cell asfunction of latitude:

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Reasons 1 and 2 sufficient for a Call for Data (to maintain up-to-date CL-DB for policy support)

However, biodiversity aspects ever more relevant

Thus, biodiv-related CLs are encouraged

In the following: sketch of a possible way to derivebiodiv-related N & S critical load functions

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Level 0:

- CLnutN is determined from a critical [N] (or empirical CL) related to (be avoided) biodiv-change- Acidity CL function is derived for a (e.g.) critical pH

related to (be avoided) biodiv-change

CLs for acidity and nutrient N combined into aCL function of N and S (dark grey area)

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

New Level:

Derive N and S CL function from (your favourite)biodiversity model …

e.g. PROPS, MultiMOVE, BERN, Veg, …, empirical, …

… e.g., along the following lines (using PROPS) …

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

PROPS model summary:

Probability y for occurrence of a plant modelled as:

n

i

n

i

n

jjijiii xxaxaa

y

yyz

1 1 1,01

log)logit(

with ai,j = aj,i for all i,j. Number of variables xi is n = 4 (normalized/log-transformed): soil solution pH and [N], precipitation, temperature.

Probability y obtained as:)exp(1

1

zy

The 15 coefficients for many plant species are derived from relevés with both biotic and abiotic observations and extrapolated …

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

PROPS DataBase: Isolines of occurrence probability for single species (in [N]-pH plane):

Temp and Precip fixed

.. However, single plants rarely used …

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Example for an EVM vegetation unit

Scaled prob. to get all species

... But we need relationship withNdep and Sdep

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

The same as function of N and S deposition:

Computed fromphysico-chemicalsite characteristicsand steady-state model (here: SMB)

Chose a “critical”(“optimal”?)Ndep-Sdep range

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Apply limiting/critical/acceptable value of prob/poss/index, e.g.:

N & S Critical Load Function:

… or …

[can there by too littleS and/or N deposition?]

N & S Critical Load Function:

Entire grey area(dark+light) definesN & S CLF, i.e.area of non-exceedance

… simplify …

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Polygons need not be convex, but must be monotonous![ N1 ≤ N2 ≤ N3 ≤ … and S1 ≤ S2 ≤ S3 …]

Simplify to polygon with a few (<10) nodes, e.g.:

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

No!

Not allowed:

i.e. deposition increase may not lead to non-exceedance!

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Summary for Call4Data:

1. Cheap version:Convert existing CLs to 0.10⁰×0.05⁰ Lon-Lat-grid and CLaci+CLnut to 4-point N & S CLFunction

2. Better version:Revisit/update existing CLs, consider biodiv criteria and follow step 1 3. Ambitious version:Use (steady-state or dynamic) biodiv model to derive N & S CLF and follow step 1

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Thank You!

…

Comments? Questions?

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

CCE WS and ICP M&M TF, 7-10 April 2014, Rome

Choice of probability/indicator:

Product of probs. (geometric mean): Arithmetic mean: