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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: