DOI: 10.5281/zenodo.13222637
title: Dataset for the preprint: "Intercomparison of biogenic CO2 flux models in four urban parks in the city of Zurich"

description: Dataset supporting the submission of the manuscript titled "Intercomparison of biogenic CO2 flux models in four urban parks in the city of Zurich" to the to the international journal "Biogeosciences".

Meteorological data

Hourly aggregated meteorological dataset for the urban area of Zurich, originating from two urban stations: Kaserne (8°32'/47°23'), which is a station of the Swiss national air pollution monitoring network NABEL, and Hardau II (8°30'/47°23'), which is a station established for the ICOS-Cities project.  Zurich Kaserne is located in a large courtyard. Wind and global radiation are measured on top of a four-storey building. Wind is measured at 35 m and global radiation at 27 m above ground. Hardau II station is established on the top of a high-rise building (110 m a.g.l.). Meteorological observation gaps were filled using Copernicus ERA5-Land data.

Data format: comma separated values (csv)

Time step: 60 min (aggregated)

Time stamp: yyyy-MM-dd HH:mm, UTC, end of aggregated period

Period: 01/2022–09/2023

Monthly mean atmospheric CO2 concentration data derived from the ICOS-Cities Hardau II station (07/2022–09/2023) and the Beromunster station (11/2012–02/2022). Observation gaps were filled using Copernicus ERA5-Land data.

Further information on the dataset can be found in the submitted manuscript. 

Data format: comma separated values (csv)

Time step: Monthly (mean)

Time stamp: yyyy-MM-dd 

Period: 11/2012–09/2023






Variable



Acronym



Units



Height above ground



Location



Geographic location





Global radiation



G



W m-2



27 m



Kaserne



8°32'/47°23'





Air temperature



Tair



Degrees Celsius



2 m



Kaserne



8°32'/47°23'





Relative humidity



RH



%



2 m



Kaserne



8°32'/47°23'





Air pressure



P



hPa



2 m



Kaserne



8°32'/47°23'





Wind speed



u



m s-1



35 m



Kaserne



8°32'/47°23'





Precipitation



R



mm



2 m



Kaserne



8°32'/47°23'





Downward longwave radiation



LW



W m-2



110 m



Hardau II, ERA-5



8°30'/47°23'





Soil temperature



Tsoil



Degrees Celsius



-0.15 m



Parks



-





Soil water content



SWC



m3 m-3



-0.15 m



Parks



-





Atmospheric CO2 concentration



CO2



ppmv



2 m



Hardau II, Beromunster, ERA-5



8°30'/47°23', 8°10'/47°11





 

In-situ ecophysiological data

In-situ ecophysiology measurements performed on park trees and lawns in the city of Zurich during the ICOS-Cities project.

LAI (leaf area index) was measured in dense Platanus sp. tree stands, found only in Bullingerhof and Hardaupark, during sunny conditions using a ceptometer (SS1 SunScan, Delta-T Devices).

Sap flow was measured at six trees (Platanus sp., Tilia sp.), at Bullingerhof, Hardaupark and Fritschiwiese, with heat pulse sap flow sensors (3 x 3 cm probes, Implexx Sense), providing continuous measurements at 10-min sampling intervals. Daily aggregated sap flux densities (cm3 cm−2 d−1) were calculated from the 10-min data using the sensor inner thermistors, averaged for the six sampled trees.

Soil and grass respiration were measured using a portable CO2 soil efflux system equipped with a 20 cm diameter survey chamber (LI-8200-01S, LI-COR Biosciences) and a CO2/H2O analyser (LI-870, LI-COR Biosciences). The observations originate from a total of 10 soil collars (Bullingerhof, Hardaupark, Fritschiwiese, Heiligfeld) separated to undisturbed grass collars (Reco, μmol CO2 m-2 s-1) and collars where the aboveground grass was clipped (Rsoil, μmol CO2 m-2 s-1).

Further information on the dataset can be found in the submitted manuscript.

Data format: comma separated values (csv)

Time stamp: yyyy-MM-dd

Period: 04/2022–09/2023

 

Land cover map

Land cover map of part of Zurich urban area. Datasets used to derive this map:



·        Land Use Cadastre of the Canton of Zurich (https://www.geolion.zh.ch/geodatensatz/show?gdsid=443)

·        Urban Atlas (https://doi.org/10.2909/fb4dffa1-6ceb-4cc0-8372-1ed354c285e6)

·        Vegetation Height Model (VHM) from the Swiss federal forest inventory (https://opendata.swiss/de/dataset/vegetationshohenmodell-lfi)

·        Forest Mixture from the Swiss Federal Forest Inventory (https://opendata.swiss/de/dataset/waldmischungsgrad-lfi)


Further information on the dataset can be found in the submitted manuscript.

 

Data specifications:

CRS: EPSG:32632 - WGS 84 / UTM zone 32N - Projected

Spatial Extent: 461972.1, 5246490.4 : 463972.1, 5248490.4

Temporal Extent: 2023

Units: meters

Width: 2000

Height: 2000

Bands: 1

Pixel Size: 1,-1

Data type: Float32 - Thirty two bit floating point

GDAL Driver Description: GTiff

GDAL Driver Metadata: GeoTIFF

 

Legend:

30           Grass

40           Crops

50           Paved

60           Buildings

70           Deciduous trees

80           Water

 

CO2 fluxes

Hourly mean CO2 fluxes estimated by the models diFUME, JSBACH, SUEWS and VPRM for the trees and lawns of the Zurich urban parks: Bullingerhof, Hardaupark, Fritschiwiese and Heiligfeld. GPP stands for gross primary productivity, Reco for ecosystem respiration and NEE for net ecosystem exchange. All fluxes are in units: μmol CO2 m-2 s-1.

The parameter sets used by each model are presented in the Tables below. Further information on the dataset can be found in the submitted manuscript.

Parameters used by diFUME model






Parameter



Value



Units



Description





A_max



15



μmol CO2 m-2 s-1



maximum leaf gross photosynthetic rate





a



0.045



mol CO2 mol-1 PAR



quantum yield for CO2 assimilation





a_1



25



N/A



empirical coefficient in Leuning (1995) model





b_



0.65



N/A



empirical coefficient in β-factor formula





b_1



5



N/A



empirical coefficient





D_o



0.3



kPa



empirically determined coefficient for the VPD scalar inside Leuning (1995) model





D_sc



1



N/A



daylight scalar for dark respiration inhibition during day (1: no inhibition)





E_0



487.75



K



temperature sensitivity parameter for soil respiration





g_o



0.01



mol CO2 m-2 s-1



residual stomatal conductance for CO2 (g_s when Anet = 0, PAR = 0).





Q_10



1.85



N/A



temperature sensitivity of leaf respiration





R_(l,ref)



1.53



μmol CO2 m-2 s-1



reference leaf respiration at Tair = 25 °C





R_(S,ref)



2.49



μmol CO2 m-2 s-1



reference soil respiration at Tsoil = 10 °C





T_opt



23



°C



optimum air temperature for gross photosynthesis





T_0



-46



°C



low-temperature limit for soil respiration





T_(ref,S)



10



°C



reference soil temperature for soil respiration





T_(ref,l)



25



°C



reference air temperature for leaf respiration





W



10



°C



width of the bell-shape curve at f(T_air )  = 0.5





θ_ref



0.4



m3 m-3



saturated soil volumetric water content 





θ_g



0.1



m3 m-3



minimum soil volumetric water content, limit to stomatal conductance





θ_0



0.04



m3 m-3



minimum soil volumetric water content, limit to soil respiration





 

Parameters used by JSBACH model






Parameter



Trees



Lawn



Units



Description





J_max



104.5



148.6



μmol(CO2) m-2(leaf) s-1



Maximum electron transport rate at 25 °C





T_alt



4.0–4.5



 



°C



Alternation temperature





θ_cap



0.32– 0.39



0.32– 0.34



m m-1



Volumetric soil field capacity





θ_pwp



0.13– 0.21



0.135–0.165



m m-1



Volumetric wilting point





V_max



55.0



78.2



μmol(CO2) m-2(leaf) s-1



Maximum carboxylation rate at 25 °C





z_root



0.5



0.12



m



Root depth





CC



1.25



1.25



N/A



Relative cost to produce one carbon





f_faeces



0.3



0.3



N/A



Fraction of carbon from herbivore faeces that goes into the green litter pool





f_leaf



0.4



0.4



N/A



A fixed fraction of canopy maintenance respiration that makes up the dark respiration





k



0.1



0.09



N/A



LAI growth rate during growth phase





LAI_max



3.6–4.1



3.0



m2 m-2



Maximum leaf area index





p



veg:

0.004

rest:

0.1



growth:

0.1

dry:

0.015



N/A



LAI shedding rate (trees: vegetative and rest phase; grass: growth and dry season)





r_d



0.605



0.8602



μmol(CO2) m-2(leaf) s-1



Dark respiration at 25 °C, fraction of Vmax





 

Parameters used by SUEWS model






Parameter



Trees



Lawn



Units



Description





f_i



0.21



0.18



N/A



Fraction of each vegetation type i





F_(pho,max,i)



8.3



8.92



μmol m-2 s-1



Maximum potential photosynthesis





LAI_(max,i)



4.8



3



m2 m-2



Full leaf-on summertime value





LAI_(min,i)



0.66



1.6



m2 m-2



Leaf-off wintertime value





T_L



-10



-10



°C



Lower air temperature limit





T_H



55



55



°C



Upper air temperature limit





G_5



30



30



°C



Parameter related to temperature dependence





G_3



0.66



0.538



N/A



Parameter related to VPD dependence





G_4



0.89



0.87



N/A



Parameter related to VPD dependence





G_6



0.36



0.55



mm-1



Parameter related to soil moisture dependence





G_2



477



263.5



W m-2



Parameter related to  dependence





Δθ_WP



132.5



143



mm



Wilting point deficit





K_(↓max)



1200



1200



W m-2



Maximum incoming shortwave radiation





a_i



0.78



1.7



N/A



Empirical soil and vegetation respiration coefficient





b_i



0.08



0.06



N/A



Empirical soil and vegetation respiration coefficient





ω_(1,GDD,i)



0.04



0.04



N/A



Parameter for LAI calculation





ω_(2,GDD,i)



0.0005



0.0005



N/A



Parameter for LAI calculation





ω_(1,SDD,i)



-1.5



-1.5



N/A



Parameter for LAI calculation





ω_(1,SDD,i)



0.0025



0.0025



N/A



Parameter for LAI calculation





GDD



300



300



days



The growing degree days (GDD) needed for full capacity of the leaf area index





SDD



-300



-300



days



The senescence degree days (SDD) needed to initiate leaf off





T_(base,GDD)



5



5



°C



Base Temperature for initiating growing degree days (GDD) for leaf growth





T_(base,SDD)



10



10



°C



Base temperature for initiating senescence degree days (SDD) for leaf off





 

Parameters used by VPRM model






Parameter



Trees



Lawn



Units



Description





λ





-0.16






-0.13






μmol CO2 m-2 s-1






light use efficiency






PAR_0





356.99






545.61






μmol m-2 s-1






half-saturation value






α





0.22






0.40






μmol CO2 m-2 s-1 /0C






empirical coefficient






β





1.09






0.42






μmol CO2 m-2 s-1






empirical coefficient






T_max





40






40






°C 






maximum temperature for photosynthesis






T_min





0






2






°C 






minimum temperature for photosynthesis






T_opt





20






18






°C 






optimal temperature for photosynthesis






T_low





0






0






°C 






to account for the persistence of soil respiration in winter






 

Data format: comma separated values (csv)

Time step: 60 min (aggregated)

Time stamp: yyyy-MM-dd HH:mm, UTC, end of aggregated period

Period: 01/2022–09/2023