Cluster Analysis for Object-Oriented Verification of Fields: A Variation

Marzban, Caren; Sandgathe, Scott
March 2008
Monthly Weather Review;Mar2008, Vol. 136 Issue 3, p1013
Academic Journal
In a recent paper, a statistical method referred to as cluster analysis was employed to identify clusters in forecast and observed fields. Further criteria were also proposed for matching the identified clusters in one field with those in the other. As such, the proposed methodology was designed to perform an automated form of what has been called object-oriented verification. Herein, a variation of that methodology is proposed that effectively avoids (or simplifies) the criteria for matching the objects. The basic idea is to perform cluster analysis on the combined set of observations and forecasts, rather than on the individual fields separately. This method will be referred to as combinative cluster analysis (CCA). CCA naturally lends itself to the computation of false alarms, hits, and misses, and therefore, to the critical success index (CSI). A desirable feature of the previous method—the ability to assess performance on different spatial scales—is maintained. The method is demonstrated on reflectivity data and corresponding forecasts for three dates using three mesoscale numerical weather prediction model formulations—the NCEP/NWS Nonhydrostatic Mesoscale Model (NMM) at 4-km resolution (nmm4), the University of Oklahoma’s Center for Analysis and Prediction of Storms (CAPS) Weather Research and Forecasting Model (WRF) at 2-km resolution (arw2), and the NCAR WRF at 4-km resolution (arw4). In the small demonstration sample herein, model forecast quality is efficiently differentiated when performance is assessed in terms of the CSI. In this sample, arw2 appears to outperform the other two model formulations across all scales when the cluster analysis is performed in the space of spatial coordinates and reflectivity. However, when the analysis is performed only on spatial data (i.e., when only the spatial placement of the reflectivity is assessed), the difference is not significant. This result has been verified both visually and using a standard gridpoint verification, and seems to provide a reasonable assessment of model performance. This demonstration of CCA indicates promise in quickly evaluating mesoscale model performance while avoiding the subjectivity and labor intensiveness of human evaluation or the pitfalls of non-object-oriented automated verification.


Related Articles

  • Validation of precipitation over Japan during 1985-2004 simulated by three regional climate models and two multi-model ensemble means. Ishizaki, Yasuhiro; Nakaegawa, Toshiyuki; Takayabu, Izuru // Climate Dynamics;Jul2012, Vol. 39 Issue 1/2, p185 

    We dynamically downscaled Japanese reanalysis data (JRA-25) for 60 regions of Japan using three regional climate models (RCMs): the Non-Hydrostatic Regional Climate Model (NHRCM), modified RAMS version 4.3 (NRAMS), and modified Weather Research and Forecasting model (TWRF). We validated their...

  • Assessing the simulation and prediction of rainfall associated with the MJO in the POAMA seasonal forecast system. Marshall, Andrew; Hudson, Debra; Wheeler, Matthew; Hendon, Harry; Alves, Oscar // Climate Dynamics;Dec2011, Vol. 37 Issue 11/12, p2129 

    We assess the ability of the Predictive Ocean Atmosphere Model for Australia (POAMA) to simulate and predict weekly rainfall associated with the MJO using a 27-year hindcast dataset. After an initial 2-week atmospheric adjustment, the POAMA model is shown to simulate well, both in pattern and in...

  • Predictability of Tropical Pacific Decadal Variability in an Intermediate Model. Karspeck, Alicia R.; Seager, Richard; Cane, Mark A. // Journal of Climate;Jul2004, Vol. 17 Issue 14, p2842 

    The Zebiak–Cane (ZC) model for simulation of the El Niño–Southern Oscillation is shown to be capable of producing sequences of variability that exhibit shifts in the time-mean state of the eastern equatorial Pacific that resemble observations of tropical Pacific decadal...

  • Evaluation of WRF and HadRM Mesoscale Climate Simulations over the U.S. Pacific Northwest. Zhang, Yongxin; Dulière, Valérie; Mote, Philip W.; Salathé Jr., Eric P. // Journal of Climate;Oct2009, Vol. 22 Issue 20, p5511 

    This work compares the Weather Research and Forecasting (WRF) and Hadley Centre Regional Model (HadRM) simulations with the observed daily maximum and minimum temperature (Tmax and Tmin) and precipitation at Historical Climatology Network (HCN) stations over the U.S. Pacific Northwest for...

  • Classifying North Atlantic Tropical Cyclone Tracks by Mass Moments. Nakamura, Jennifer; Lall, Upmanu; Kushnir, Yochanan; Camargo, Suzana J. // Journal of Climate;Oct2009, Vol. 22 Issue 20, p5481 

    A new method for classifying tropical cyclones or similar features is introduced. The cyclone track is considered as an open spatial curve, with the wind speed or power information along the curve considered to be a mass attribute. The first and second moments of the resulting object are...

  • Two distinct influences of Arctic warming on cold winters over North America and East Asia. Kug, Jong-Seong; Jeong, Jee-Hoon; Jang, Yeon-Soo; Kim, Baek-Min; Folland, Chris K.; Min, Seung-Ki; Son, Seok-Woo // Nature Geoscience;Oct2015, Vol. 8 Issue 10, p759 

    Arctic warming has sparked a growing interest because of its possible impacts on mid-latitude climate. A number of unusually harsh cold winters have occurred in many parts of East Asia and North America in the past few years, and observational and modelling studies have suggested that...

  • Modeling the hydroclimatology of the midwestern United States. Part 2: future climate. Winter, Jonathan; Eltahir, Elfatih // Climate Dynamics;Feb2012, Vol. 38 Issue 3/4, p595 

    An ensemble of six 22-year numerical experiments was conducted to quantify the response of soil moisture to multiple climate change scenarios over the American Midwest. Regional Climate Model version 3 (RegCM3) was run using two surface physics schemes: Integrated Biosphere Simulator (IBIS) and...

  • Performance of CMIP5 models in the simulation of climate characteristics of synoptic patterns over East Asia. Wang, Yongdi; Jiang, Zhihong; Chen, Weilin // Journal of Meteorological Research;Aug2015, Vol. 29 Issue 4, p594 

    The evolution of daily synoptic weather patterns is the main driver of day-to-day weather change. These patterns are generally associated with changes in temperature, precipitation, etc., especially during extreme weathers. Evaluating the ability of climate models to reproduce the frequency and...

  • Seasonal forecast of French Mediterranean heavy precipitating events linked to weather regimes. Guérémy, J. -F.; Laanaia, N.; Céron, J. -P.; Llasat, M. -C. // Natural Hazards & Earth System Sciences;2012, Vol. 12 Issue 7, p2389 

    Seasonal predictability of local precipitation is rather weak in the mid-latitudes. This is the case when assessing the skill of the seasonal forecast of Heavy Precipitating Event (HPE) extreme occurrence over the French Mediterranean coast during the fall season. Tropics to extratropics...


    Comparing statistical estimates for the long-run temperature effect of doubled CO2 with those generated by climate models begs the question, is the long-run temperature effect of doubled CO2 that is estimated from the instrumental temperature record using statistical techniques consistent with...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics