Sentences with phrase «sd precipitation anomaly»

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).

In addition, the number of multiyear periods in which a — 0.5 SD precipitation anomaly co-occurs with a 0.5 SD temperature anomaly more than doubles between the Historical and RCP8.5 experiments (Fig. 4A).

All 20 August — July 12 - mo periods that exhibited a — 1.0 SD PMDI anomaly also exhibited a — 0.5 SD precipitation anomaly (Fig. 1B and 2E), suggesting that moderately low precipitation is prerequisite for a 1 - SD drought year.

In addition, the probability of a — 1.5 SD precipitation anomaly increases in spring (P < 0.001) and autumn (P = 0.01) in 2006 — 2080 relative to 1920 — 2005, with spring occurrence increasing by ∼ 75 % and autumn occurrence increasing by ∼ 44 % — which represents a substantial and statistically significant increase in the risk of extremely low - precipitation events at both margins of California's wet season.

P values are shown for the difference in occurrence of — 1.5 SD precipitation anomalies between the Historical period (1920 — 2005) and the RCP8.5 period (2006 — 2080).

However, the occurrence of — 0.5 SD precipitation anomalies has not increased in recent years (40 % in 1896 — 2014 and 40 % in 1995 — 2014)(Fig. 2 A and B).

Not exact matches

We consider «moderate» temperature and precipitation anomalies to be those that exceed 0.5 SDs («0.5 SD») and «extreme» temperature and precipitation anomalies to be those that exceed 1.5 SDs («1.5 SD»).

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).

(D) The unconditional probability of a — 1.5 SD seasonal precipitation anomaly (blue curve) and the conditional probability that a — 1.5 SD seasonal precipitation anomaly occurs in conjunction with a 1.5 SD seasonal temperature anomaly (red curve), for each of the four 3 - mo seasons.

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).

The Bottom panels (C and D) show the unconditional probability (across the ensemble) that the annual precipitation anomaly is less than — 0.5 SDs, and the conditional probability that both the annual precipitation anomaly is less than — 0.5 SDs and the temperature anomaly is greater than 0.

During 1995 — 2014, 6 of the 8 moderately dry years produced 1 - SD drought (Fig. 1A), with all 6 occurring in years in which the precipitation anomaly exceeded — 0.5 SD and the temperature anomaly exceeded 0.5 SD (Fig. 1C).

(A) Histogram of the frequency of occurrence of consecutive August — July 12 - mo periods in which the 12 - mo precipitation anomaly is less than — 0.5 SDs and the 12 - mo temperature anomaly is at least 0.5 SDs, in historical observations and the LENS large ensemble experiment.

Most 1 - SD drought years have occurred when conditions were both dry (precipitation anomaly < 0) and warm (temperature anomaly > 0), including 15 of 20 1 - SD drought years during 1896 — 2014 (Fig. 2A and Fig.

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