Maize-Grain - annual potential evapotranspiration deficit under maize (to mid and end of century)


Maize-Grain - Annual potential evapotranspiration deficit (PED) is the sum of daily PED under maize grain over a year (starting July).
The six-model ensemble mean of annual-mean climatologies are provided for the historical baseline (1986-2005), annual PED mid-century (2031-2050) and end of century (2081-2100) for four Representive Concentration Pathways (RCP) of future anthropogenic emissions.
The change in annual PED is the ensemble mean of the difference between the 20-year mean annual PED mid-century (2031-2050) or the end of the century (2081-2100), and the 20 years mean annual PED of the historical baseline (1986-2005) of the six models.
The soil data used in the water balance model is derived from S-map and the fundamental soil layers. No data cells are where the temperature was insufficient for sowing.


Date: September 2023 Version: v1

Owner: NIWA, PFR and Manaaki Whenua - Landcare Research

Contact: Jing Guo, Manaaki Whenua - Landcare Research


Link to report / paper

  1. Mullan A., Sood A, Stuart S 2016. Climate Change Projections for New Zealand
  2. Sood, A., Mullan, B. (2020). Projected changes in New Zealand drought risk: an updated assessment using multiple drought indicators. NIWA Client Report 202001WN1
  3. Sood A, Lilburne L, Carrick S, Yang Y, Srinivasan R, Pollacco J, Porteous A 2021. Projected changes in New Zealand Drought Risk. NIWA Client Report 2021WN1


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Dataset attributes

Spatial extent New Zealand
Spatial resolution 5x5 km2
Temporal extent
Temporal resolution Annual and seasonal climatologies
Evaluation method (Validation) None
Evaluation result (Numeric) None
Evaluation result (Categorical)
Uncertainty method This dataset consists of six-model ensemble mean annual and seasonal climatologies. Further analysis to assess the uncertainty is not yet attempted.
Uncertainty data format (Numeric) None
Uncertainty data format (Categorical) None



The procedure to derive the potential evapotranspiration deficit (PED) for maize using NIWA's soil water balance model. A pasture version of this dataset is described in more detail in earlier reports [1,2].
The soil moisture and PED are computed using spatially distributed hydrology parameters dervived from S-map (MWLR) dataset and VCSN climate observations (NIWA) on the same grid nationally for validation against observations [3]. The growth parameters for maize are derived from the literature and Apsim modelling.


Fitness for purpose / limitations

This table indicates whether the dataset is suitable for different types of questions at different scales.

Note: Users should carefully consider their purpose as this dataset may not be suitable.

Operational Absolute Relative Screening/scoping
Block/farm No No No Maybe
Multi-farms(5+) Maybe Maybe Maybe Yes
Catchment Yes Yes Yes Yes
National/regional Yes Yes Yes Yes
Caveat(s) The climate and soil information is too coarse for use at finer scales.

Data and Resources