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Onions - critical climate risks

Description

The key climate risks for onions have been characterised in terms of the sensitive period and the critical threshold. Each risk layer shows the mean number of days in the sensitive period that the threshold was exceeded.
The ensemble means are provided for:

  • the historical baseline (1981-2000),
  • mid-century (2041-2060) and
  • end of century (2081-2100)
for four Representive Concentration Pathways (RCP) of future anthropogenic emissions.

 

Date: December 2023 Version: v1

Owner: NIWA

Contact: Edmar Teixiera, PFR

 

Preview Image

 

Dataset attributes

Spatial extent New Zealand
Spatial resolution NIWA Virtual Climate Station Network 5km climate grid
Temporal extent 20 year historical past, mid and end of century
Temporal resolution Annual
Evaluation method (Validation) N/A
Evaluation result (Numeric) N/A
Evaluation result (Categorical) N/A
Uncertainty method Not supplied but an estimate of uncertainty can be generated by assessing the variability of estimates between years and GCMs
Uncertainty data format (Numeric)
Uncertainty data format (Categorical)

 

Methodology

The annual number of days of exceedance of each threshold is calculated for each of six Global Climate Models (GCM).
An ensemble average of the number of days from the 6 models and 20 years is calculated over the historical baseline (1981-2000), mid-century (2041-2060) and end of century (2081-2100) under the 2.6, 4.5, 6.0, and 8.5 RCP scenarios.

The thresholds for onions:

Crop Sensitive period (date) Climate variables Critical value Risk
Onions 01 Jan - 29 Feb Tmax > 31⁰ Heat stress
01 Nov - 30 Nov Tmin < 0⁰ Frost
01 Jan - 31 Mar PCP > 3 days in any 7 day with ≥ 5 mm/day Extreme rainfall

 

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 Maybe Maybe
Multi-farms(5+) No No Yes Yes
Catchment No No Yes Yes
National/regional No No Yes Yes
Caveat(s) Does not include micro climate. Climate change projections are very uncertain. Does not account for change in the sensitive periods.

Data and Resources