Projected changes in air temperature, fulfillment of chilling requirement and onset of flowering.

<p>Projected with 5 (ECH5-REMO/CLM) and 8 (ENSEMBLES) climate runs and five () and seven () phenological models for Lower Saxony (area mean), relative to the 1971–2000 mean. : single year-mean, min-to-max range of climate runs (shaded area), 10 year moving average of each run (solid lines, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075033#pone.0075033.s001" target="_blank">Methods S1</a> for equation). , : BBCH 65, early ripeners, 30-year-moving-average, all impact model mean (solid white line), single model range (shaded areas). The range of each phenological model (min-to-max) obtained from climate runs is plotted with 20% transparency (darker areas illustrate coinciding results).</p

Overview of employed data.

a<p>German Meteorological Service. Phenological observation program. URL: <a href="http://www.dwd.de" target="_blank">http://www.dwd.de</a> (April 20, 2013).</p>b<p>air temperature at 2 m elevation.</p>c<p>German Meteorological Service. Station network. URL: <a href="http://www.dwd.de" target="_blank">http://www.dwd.de</a> (April 20, 2013).</p>d<p>“UBA”-Run, experiments 6215/6221.</p>e<p>“BFG”-Run, experiments 29001/29002.</p>f<p>experiments 1518/1518, Max Planck Institute for Meteorology, Hamburg, Germany.</p

Changes in bloom and blossom frost risk as projected by different phenological models and climate runs 1–5.

<p>Early ripeners, BBCH 65, temperature threshold 0°C, reference period 1971–2000, resolution 0.1°. White fields denote non-significant results, black fields denote missing/insufficient data. 1–99% percentile range.  = 1985 and 2084,  = grid point.</p

Distribution of projected changes in blossom frost risk by the end of the 21st century (2070–2099 minus 1971–2000) for early and late ripening varieties, phenophases BBCH 60 and 65 and 7 phenological models:

<p>Temperature thresholds °C and °C; inter-quartile range across 13 climate runs; phenological models are presented by same colors. Calculated from all grid points (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075033#pone.0075033.s001" target="_blank">Methods S1</a> for equation).</p

Stepwise error of simulation chain segments. SE: Simulation error, ABS: absolute level from measured data.

a<p>min-to-max range across all ripening groups and phenophases.</p>b<p>min-to-max range across all ripening groups, phenophases and phenological models.</p>c<p>Mean absolute error (MAE), average over all grid points.</p>d<p>Error from comparison of measured blossom frost risk with blossom frost risk simulated with measured temperature (1991–2012).</p>e<p>Error from comparison of blossom frost risk simulated with measured temperature with blossom frost risk simulated.</p><p>with simulated temperature (1951–2012).</p

Changes in bloom and blossom frost risk as projected by different phenological models and climate runs 6–13.

<p>Early ripeners, BBCH 65, temperature threshold 0°C, reference period 1971–2000, resolution 0.2°. White fields denote non-significant results, black fields denote missing/insufficient data. 1–99% percentile range.  = 1985 and 2084,  = grid point.</p

Phenological models.

a<p>For model 1, t1 was set to January 1.</p

Uncertainty in the projection of apple bloom ().

<p>Drawn from phenological impact models 2–7 and 13 climate projections. Mean uncertainty of phenophases (BBCH 60, 65) and ripening groups (early, late).</p

Scheme of used input data and projection.

<p>Note that for simulated temperature the grid of the regional climate model CLM is shown exemplarily.</p

Published projections of future apple blossom frost risk.

a<p>Tests on blossom frost risk.</p>b<p>depending on subregion.</p