Skill Assessment of North American Multi-Models Ensemble (NMME) for June-September (JJAS) Seasonal Rainfall over Ethiopia

Abstract This study provides an empirical description of intraseasonal rainfall variability within the North American monsoon (NAM) region. Applying particular definitions to historical daily rainfall observations, it demonstrates that distinct intraseasonal rainfall modes exist and that these modes differ considerably from the monsoon core region in northwest Sonora (SON), California, to its northward extension in southeast Arizona (AZ). To characterize intraseasonal rainfall variability (ISV), separate P-mode principal component (PC) analyses were performed for SON and AZ. The results indicate that in each area, much of the ISV in rainfall can be described by three orthogonal modes. The correlations between ISV modes and total seasonal rainfall reinforce the notion of differing behaviors between the monsoon’s core and extension. For SON all three ISV modes exhibit significant correlation with seasonal rainfall, with the strongest relationship in evidence for the ISV mode, which is related to rainfall intensity. For AZ, total rainfall exhibits the strongest correlation with the ISV mode, which emphasizes season length and rainfall consistency. Examination of longer-period behavior in the ISV modes indicates that, for SON, there is a positive linear trend in intensity, but a countervailing trend toward a shorter monsoon season along with less consistent rainfall in the form of shorter wet spells. For AZ, the evidence for trend in the ISV modes is not nearly as compelling, though one of the modes appears to exhibit distinct multidecadal variability. This study also evaluates teleconnectivity between ENSO, the Pacific decadal oscillation (PDO), and the NAM’s intraseasonal rainfall variability. Results indicate that part of the intraseasonal rainfall variability in both SON and AZ is connected to ENSO while only SON exhibits a teleconnection with the long-period fluctuations of the PDO.

Download Full-text

Probabilistic Seasonal Forecasts in the North American Multimodel Ensemble: A Baseline Skill Assessment

Journal of Climate ◽

10.1175/jcli-d-14-00862.1 ◽

2016 ◽

Vol 29 (8) ◽

pp. 3015-3026 ◽

Cited By ~ 30

Author(s):

Emily Becker ◽

Huug van den Dool

Keyword(s):

Surface Temperature ◽

North American ◽

High Reliability ◽

Skill Assessment ◽

Seasonal Forecasts ◽

Multimodel Ensemble ◽

The North ◽

Probabilistic Forecasts ◽

Geographical Regions ◽

North American Multimodel Ensemble

Abstract The North American Multimodel Ensemble (NMME) forecasting system has been continuously producing seasonal forecasts since August 2011. The NMME, with its suite of diverse models, provides a valuable opportunity for characterizing forecast confidence using probabilistic forecasts. The current experimental probabilistic forecast product (in map format) presents the most likely tercile for the seasonal mean value, chosen out of above normal, near normal, or below normal categories, using a nonparametric counting method to determine the probability of each class. The skill of the 3-month-mean probabilistic forecasts of 2-m surface temperature (T2m), precipitation rate, and sea surface temperature is assessed using forecasts from the 29-yr (1982–2010) NMME hindcast database. Three forecast configurations are considered: a full six-model NMME; a “mini-NMME” with 24 members, four each from six models; and the 24-member CFSv2 alone. Skill is assessed on the cross-validated hindcasts using the Brier skill score (BSS); forecast reliability and resolution are also assessed. This study provides a baseline skill assessment of the current method of creating probabilistic forecasts from the NMME system. For forecasts in the above- and below-normal terciles for all variables and geographical regions examined in this study, BSS for NMME forecasts is higher than BSS for CFSv2 forecasts. Niño-3.4 forecasts from the full NMME and the mini-NMME receive nearly identical BSS that are higher than BSS for CFSv2 forecasts. Even systems with modest BSS, such as T2m in the Northern Hemisphere, have generally high reliability, as shown in reliability diagrams.

Download Full-text

Infection control in North American dental schools

Journal of Dental Education ◽

10.1002/j.0022-0337.1989.53.9.tb02344.x ◽

1989 ◽

Vol 53 (9) ◽

pp. 532-537 ◽

Cited By ~ 1

Author(s):

E Sampson ◽

VB Dhuru

Keyword(s):

Infection Control ◽

North American ◽

Dental Schools

Download Full-text

Treatment planning instruction in North American dental schools, 1984-85

Journal of Dental Education ◽

10.1002/j.0022-0337.1985.49.10.tb01933.x ◽

1985 ◽

Vol 49 (10) ◽

pp. 702-706

Author(s):

S Kennon ◽

TF Sleamaker ◽

AG Farman

Keyword(s):

Treatment Planning ◽

North American ◽

Dental Schools

Download Full-text

Adaptation of the Connected Speech Test: Rerecording and Passage Equivalency

American Journal of Audiology ◽

10.1044/2019_aja-19-00052 ◽

2020 ◽

Vol 29 (2) ◽

pp. 259-264 ◽

Cited By ~ 2

Author(s):

Hasan K. Saleh ◽

Paula Folkeard ◽

Ewan Macpherson ◽

Susan Scollie

Keyword(s):

Speech Perception ◽

North American ◽

First Language ◽

Intraclass Correlation ◽

Normal Hearing ◽

Connected Speech ◽

Internal Reliability ◽

Speech Test ◽

The Mean ◽

Unit Standard

Purpose The original Connected Speech Test (CST; Cox et al., 1987) is a well-regarded and often utilized speech perception test. The aim of this study was to develop a new version of the CST using a neutral North American accent and to assess the use of this updated CST on participants with normal hearing. Method A female English speaker was recruited to read the original CST passages, which were recorded as the new CST stimuli. A study was designed to assess the newly recorded CST passages' equivalence and conduct normalization. The study included 19 Western University students (11 females and eight males) with normal hearing and with English as a first language. Results Raw scores for the 48 tested passages were converted to rationalized arcsine units, and average passage scores more than 1 rationalized arcsine unit standard deviation from the mean were excluded. The internal reliability of the 32 remaining passages was assessed, and the two-way random effects intraclass correlation was .944. Conclusion The aim of our study was to create new CST stimuli with a more general North American accent in order to minimize accent effects on the speech perception scores. The study resulted in 32 passages of equivalent difficulty for listeners with normal hearing.

Download Full-text