The role of confidence and diversity in dynamic ensemble class prediction systems

2015 ◽  
Author(s):  
Şenay Yaşar Sağlam
2021 ◽  
Author(s):  
Shuting Yang ◽  
Tian Tian ◽  
Yiguo Wang ◽  
Torben Schmith ◽  
Steffen M. Olsen ◽  
...  

<p>The subpolar North Atlantic (SPNA) is a region experiencing substantial decadal variability, which has been linked to extreme weather impacts over continents. Recent studies have suggested that the connectivity with the SPNA may be a key to predictions in high latitudes. To understand the impact of the SPNA on predictability of North Atlantic-European sectors and the Arctic, we use two climate<strong> </strong>prediction systems, EC-Earth3-CPSAI and NorCPM1, to perform ensemble pacemaker experiments with a focus on the subpolar extreme cold anomaly event in 2015. This 2015 cold anomaly event is generally underestimated by the decadal prediction systems. In order to force the model to better represent the observed anomaly in SPNA, we apply nudging in a region of the SPNA (i.e., 51.5°W - 13.0°W, 30.4°N - 57.5°N, and from surface to 1000 m depth in the ocean). Here ocean temperature and salinity is restored to observed conditions from reanalysis in both model systems. All other aspects of the setup of this pacemaker experiment follow the protocol for the CMIP6 DCPP-A hindcasts and initialized on November 1, 2014. The restoration is applied during the hindcasts from November 2014 to December 2019. Multi-member ensembles of 10-year hindcasts are performed with 10 members for the EC-Earth3-CPSAI and 30 members for the NorCPM1.</p><p>The time evolution of ensembles of the initialized nudging hindcasts (EXP1) is compared with the initialized DCPP-A hindcast ensembles (EXP2) and the uninitialized ensembles (EXP3). The prediction skills of the three sets of experiments are also assessed. It can be seen that restoring the ocean temperature and salinity in the SPNA region to the reanalysis improves the prediction in the region quickly after the simulation starts, as expected. On the interannual to decadal time scales, the areas with improved prediction skills extend to over almost the entire North Atlantic for both models. The improved skill over Nordic Seas is particularly significant, especially for EC-Earth3-CPSAI. For NorCPM, the regions with improved skills extend to the entire Arctic. Our results suggest the possible role of the SPNA as a source of skillful predictions on interannual to decadal time scale, especially for high latitudes. The ocean pathways are the critical source of skill whereas our results imply a limited role of coupled feedbacks through the atmosphere.  </p>


2020 ◽  
Vol 33 (14) ◽  
pp. 6141-6163
Author(s):  
Arun Kumar ◽  
Mingyue Chen

AbstractUsing extensive hindcasts from seasonal prediction systems participating in the North American Multi-Model Ensemble (NMME), possible causes for low skill in predicting seasonal mean precipitation over California during December–February (DJF) are investigated. The analysis focuses on investigating two possibilities for low prediction skill: role model biases or inherent predictability limits. The motivation for the analysis was the seasonal prediction during DJF 2015/16 that called for enhanced probability for above normal precipitation over southern California (which was consistent with expected conditions during an extreme El Niño) while the observed precipitation was below normal. Based on various analysis approaches and using hindcast datasets from multiple seasonal prediction systems, we build up the evidence that low skill in predicting seasonal mean precipitation over California is likely to be due to inherent predictability associated with a low signal-to-noise (SNR) regime. For the same set of seasonal prediction systems, the precipitation variability over California is contrasted with that over the southeast United States where prediction skill, as well as the SNR, is higher. The discussion also notes that building a knowledge base that goes beyond the well-known response to ENSO (based on the linear regression or composite techniques) has proven to be difficult and a systematic approach to reaching resolution to some of the overarching questions is required, and toward that end, a pathway is suggested.


2012 ◽  
Vol 102 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Vittorio Rossi ◽  
Tito Caffi

Although primary infection of grapevines by Plasmopara viticola requires splash dispersal of inoculum from soil to leaves, little is known about the role of rain in primary inoculum dispersal. Distribution of rain splashes from soil to grapevine canopy was evaluated over 20 rain periods (0.2 to 64.2 mm of rain) with splash samplers placed within the canopy. Samplers at 40, 80, and 140 cm above the soil caught 4.4, 0.03, and 0.003 drops/cm2 of sampler area, respectively. Drops caught at 40 and 80 cm (1.5 cm in diameter) were larger than drops at 140 cm (1.3 cm). Leaf coverage by splashed drops, total drop number, and drop size increased with an increase in the maximum intensity of rain (mm/h) during any rain period. Any rainfall led to infection in potted grapevines placed outside on leaf litter containing oospores, if the litter contained germinated oospores at the time of rain; infection severity was unrelated to rain amount or intensity. Results from vineyards also indicate that any rain can carry P. viticola inoculum from soil to leaves and should be considered a splash event in disease prediction systems. Sampling for early disease detection should focus on the lower canopy, where the probability of splash impact is greatest.


2017 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Seyed Mohammad Reza Hashemian ◽  
Behrooz Farzanegan ◽  
Alireza Jahangiri-Fard ◽  
Hossein Zargham Ahmadi ◽  
Seyed Reza Saghebi ◽  
...  

2001 ◽  
Vol 31 (3) ◽  
pp. 430-441 ◽  
Author(s):  
Christelle Hély ◽  
Mike Flannigan ◽  
Yves Bergeron ◽  
Douglas McRae

Spring and summer simulations were carried out using the Canadian Fire Behavior Prediction (FBP) and U.S. BEHAVE systems to study the role of vegetation and weather on fire behavior in the mixedwood boreal forest. Stands at Lake Duparquet (Quebec, Canada) were characterized as being deciduous, mixed-deciduous, mixed-coniferous, or coniferous, according to their conifer basal area percentage. Sampled fuel loads (litter, duff, woody debris, herbs, and shrubs) and local weather conditions (three different fire-risk classes) were used as inputs in the simulation. The predicted fire behavior variables were rate of spread (ROS), head fire intensity (HFI), and area burned. Results from ANOVA testing showed that both weather and vegetation are not always significant, and the two prediction systems qualitatively attribute the explained variance to these factors differently. The FBP System selects the weather factor as the most important factor for all fire behavior variables, whereas BEHAVE selects the vegetation factor. However, three research burns located in Ontario revealed that BEHAVE was not well adapted to the mixedwood boreal region, whereas FBP predictions were quantitatively close to observed prescribed values. Extreme fire weather is confirmed as producing large and intense fires, but differences in fire behavior among stand types exist across the full range of fire weather. Implications of climate change, vegetation, and seasonal effects on fire behavior and the forest mosaic are discussed.


JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.


2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.


2020 ◽  
Vol 43 ◽  
Author(s):  
Stefen Beeler-Duden ◽  
Meltem Yucel ◽  
Amrisha Vaish

Abstract Tomasello offers a compelling account of the emergence of humans’ sense of obligation. We suggest that more needs to be said about the role of affect in the creation of obligations. We also argue that positive emotions such as gratitude evolved to encourage individuals to fulfill cooperative obligations without the negative quality that Tomasello proposes is inherent in obligations.


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