Sentences with phrase «negative precipitation anomaly»

The probability that a negative precipitation anomaly co-occurs with a positive temperature anomaly has increased recently, with warm — dry years occurring more than twice as often in the past two decades (91 %) as in the preceding century (42 %)(Fig. 1B).

(C) The probability that a negative precipitation anomaly and a positive temperature anomaly equal to or exceeding a given magnitude occur in the same 12 - mo period, for all possible 12 - mo periods (using a 12 - mo running mean; see Materials and Methods), for varying severity of anomalies.

This increase in the occurrence of 1 - SD drought years has taken place without a substantial change in the probability of negative precipitation anomalies (53 % in 1896 — 2014 and 55 % in 1995 — 2014)(Figs. 1B and 2 A and B).

Similarly, negative precipitation anomalies are much more likely to produce 1 - SD drought if they co-occur with a positive temperature anomaly.

We find that although there has not been a substantial change in the probability of either negative or moderately negative precipitation anomalies in recent decades, the occurrence of drought years has been greater in the past two decades than in the preceding century.

Not exact matches

The averages for the last 12 months show relatively small negative or positive anomalies for precipitation in most areas of the globe.

During 2017, the season with the largest negative anomaly was the winter, making it the second driest winter in the ERA - Interim record in terms of precipitation.

Rather, the observed doubling of the occurrence of 1 - SD drought years has coincided with a doubling of the frequency with which a negative precipitation year produces a 1 - SD drought, with 55 % of negative precipitation years in 1995 — 2014 co-occurring with a — 1.0 SD PMDI anomaly, compared with 27 % in 1896 — 1994 (Fig. 1 A and B).

This increase implies a transition to a permanent condition of ∼ 100 % risk that any negative — or extremely negative — 12 - mo precipitation anomaly is also extremely warm.

The fact that the occurrence of warm and moderately dry years approaches that of moderately dry years in the last decades of the Historical experiment (Fig. 3 B and C) and that 91 % of negative precipitation years in 1995 — 2014 co-occurred with warm anomalies (Fig. 1B) suggests possible emergence of a regime in which nearly all dry years co-occur with warm conditions.

For example, during 1896 — 2014, 1 - SD drought occurred in 15 of the 28 years (54 %) that exhibited both a — 0.5 SD precipitation anomaly and a positive temperature anomaly, but in only 5 of the 20 years (25 %) that exhibited a — 0.5 SD precipitation anomaly and a negative temperature anomaly (Fig. 2A).

They simulated the impact of continued global warming into the future and found that — provided there was no geoengineering — only 11 of the 50 years between 2020 and 2070 would have negative Sahelian precipitation anomalies.