@article{ekwurzel_boneham_dalton_heede_mera_allen_frumhoff_2017, title={The rise in global atmospheric CO2, surface temperature, and sea level from emissions traced to major carbon producers}, volume={144}, ISSN={["1573-1480"]}, DOI={10.1007/s10584-017-1978-0}, abstractNote={Researchers have quantified the contributions of industrialized and developing nations’ historical emissions to global surface temperature rise. Recent findings that nearly two-thirds of total industrial CO2 and CH4 emissions can be traced to 90 major industrial carbon producers have drawn attention to their potential climate responsibilities. Here, we use a simple climate model to quantify the contribution of historical (1880–2010) and recent (1980–2010) emissions traced to these producers to the historical rise in global atmospheric CO2, surface temperature, and sea level. Emissions traced to these 90 carbon producers contributed ∼57% of the observed rise in atmospheric CO2, ∼42–50% of the rise in global mean surface temperature (GMST), and ∼26–32% of global sea level (GSL) rise over the historical period and ∼43% (atmospheric CO2), ∼29–35% (GMST), and ∼11–14% (GSL) since 1980 (based on best-estimate parameters and accounting for uncertainty arising from the lack of data on aerosol forcings traced to producers). Emissions traced to seven investor-owned and seven majority state-owned carbon producers were consistently among the top 20 largest individual company contributors to each global impact across both time periods. This study lays the groundwork for tracing emissions sourced from industrial carbon producers to specific climate impacts and furthers scientific and policy consideration of their historical responsibilities for climate change.}, number={4}, journal={CLIMATIC CHANGE}, author={Ekwurzel, B. and Boneham, J. and Dalton, M. W. and Heede, R. and Mera, R. J. and Allen, M. R. and Frumhoff, P. C.}, year={2017}, month={Oct}, pages={579–590} } @inproceedings{mera_rupp_mote_allen_2015, title={Attribution of trends in rising nighttime temperatures in the Western US}, author={Mera, Roberto J. and Rupp, D. and Mote, P. and Allen, M.R.}, year={2015} } @article{mera_massey_rupp_mote_allen_frumhoff_2015, title={Climate change, climate justice and the application of probabilistic event attribution to summer heat extremes in the California Central Valley}, volume={133}, ISSN={0165-0009 1573-1480}, url={http://dx.doi.org/10.1007/s10584-015-1474-3}, DOI={10.1007/s10584-015-1474-3}, abstractNote={Probabilistic event attribution (PEA) is an important tool for assessing the contribution of climate change to extreme weather events. Here, PEA is applied to explore the climate attribution of recent extreme heat events in California’s Central Valley. Heat waves have become progressively more severe due to increasing relative humidity and nighttime temperatures, which increases the health risks of exposed communities, especially Latino farmworkers and other socioeconomically disadvantaged communities. Using a superensemble of simulations with the Hadley Centre Regional Model (HadRM3P), we find that (1) simulations of the hottest summer days during the 2000s were twice as likely to occur using observed levels of greenhouse gases than in a counterfactual world without major human activities, suggesting a strong relationship between heat extremes and the increase in human emissions of greenhouse gases, (2) detrimental impacts of heat on public health-relevant variables, such as the number of days above 40 °C, can be quantified and attributed to human activities using PEA, and (3) PEA can serve as a tool for addressing climate justice concerns of populations within developed nations who are disproportionately exposed to climate risks.}, number={3}, journal={Climatic Change}, publisher={Springer Science and Business Media LLC}, author={Mera, Roberto and Massey, Neil and Rupp, David E. and Mote, Philip and Allen, Myles and Frumhoff, Peter C.}, year={2015}, month={Aug}, pages={427–438} } @article{li_mote_rupp_vickers_mera_allen_2015, title={Evaluation of a Regional Climate Modeling Effort for the Western United States Using a Superensemble from Weather@home*}, volume={28}, ISSN={0894-8755 1520-0442}, url={http://dx.doi.org/10.1175/jcli-d-14-00808.1}, DOI={10.1175/jcli-d-14-00808.1}, abstractNote={Abstract Simulations from a regional climate model (RCM) as part of a superensemble experiment were compared with observations of surface meteorological variables over the western United States. The RCM is the Hadley Centre Regional Climate Model, version 3, with improved physics parameterizations (HadRM3P) run at 25-km resolution and nested within the Hadley Centre Atmosphere Model, version 3 (HadAM3P). Overall, the means of seasonal temperature were well represented in the simulations; 95% of grid points were within 2.7°, 2.4°, and 3.6°C of observations in winter, spring, and summer, respectively. The model was too warm over most of the domain in summer except central California and southern Nevada. HadRM3P produced more extreme temperatures than observed. The overall magnitude and spatial pattern of precipitation were well characterized, though HadRM3P exaggerated the orographic enhancement along the coastal mountains, Cascade Range, and Sierra Nevada. HadRM3P produced warm/dry northwest, cool/wet southwest U.S. patterns associated with El Niño. However, there were notable differences, including the locations of the transition from warm (dry) to cool (wet) in the anomaly fields when compared with observations, though there was disagreement among observations. HadRM3P simulated the observed spatial pattern of mean annual temperature more faithfully than any of the RCM–GCM pairings in the North American Regional Climate Change Assessment Program (NARCCAP). Errors in mean annual precipitation from HadRM3P fell within the range of errors of the NARCCAP models. Last, this paper provided examples of the size of an ensemble required to detect changes at the local level and demonstrated the effect of parameter perturbation on regional precipitation.}, number={19}, journal={Journal of Climate}, publisher={American Meteorological Society}, author={Li, Sihan and Mote, Philip W. and Rupp, David E. and Vickers, Dean and Mera, Roberto and Allen, Myles}, year={2015}, month={Sep}, pages={7470–7488} } @article{mote_allen_jones_li_mera_rupp_salahuddin_vickers_2016, title={Superensemble Regional Climate Modeling for the Western United States}, volume={97}, ISSN={0003-0007 1520-0477}, url={http://dx.doi.org/10.1175/BAMS-D-14-00090.1}, DOI={10.1175/BAMS-D-14-00090.1}, abstractNote={AbstractComputing resources donated by volunteers have generated the first superensemble of regional climate model results, in which the Hadley Centre Regional Model, version 3P (HadRM3P), and Hadley Centre Atmosphere Model, version 3P (HadAM3P), were implemented for the western United States at 25-km resolution. Over 136,000 valid and complete 1-yr runs have been generated to date: about 126,000 for 1960–2009 using observed sea surface temperatures (SSTs) and 10,000 for 2030–49 using projected SSTs from a global model simulation. Ensemble members differ in initial conditions, model physics, and (potentially, for future runs) SSTs. This unprecedented confluence of high spatial resolution and large ensemble size allows high signal-to-noise ratio and more robust estimates of uncertainty. This paper describes the experiment, compares model output with observations, shows select results for climate change simulations, and gives examples of the strength of the large ensemble size.}, number={2}, journal={Bulletin of the American Meteorological Society}, publisher={American Meteorological Society}, author={Mote, Philip W. and Allen, Myles R. and Jones, Richard G. and Li, Sihan and Mera, Roberto and Rupp, David E. and Salahuddin, Ahmed and Vickers, Dean}, year={2016}, month={Feb}, pages={203–215} } @inproceedings{mera_mote_allen_2014, title={Attribution of Extreme Temperature Events for the Western US using a superensemble of Regional Climate Model Simulations}, author={Mera, Roberto J. and Mote, P. and Allen, M.R.}, year={2014} } @inproceedings{mera_ekwurzel_rupp_2014, title={Attribution of low precipitation in California during the winter of 2013-2014}, author={Mera, Roberto J. and Ekwurzel, B. and Rupp, D.}, year={2014} } @article{mera_laing_semazzi_2014, title={Moisture Variability and Multiscale Interactions during Spring in West Africa}, volume={142}, ISSN={0027-0644 1520-0493}, url={http://dx.doi.org/10.1175/mwr-d-13-00175.1}, DOI={10.1175/mwr-d-13-00175.1}, abstractNote={AbstractThe West African monsoon (WAM) is a vital source of rainfall for the African Sahel. In addition to the agricultural benefit of its rains, it benefits public health because bacterial meningitis outbreaks end with the monsoon onset. Outbreaks occur between December and May, a period of low humidity. Knowledge of the onset of high humidity could aid in predicting where the outbreaks will cease. Therefore, this study investigates the variability of atmospheric moisture during the spring over West Africa, characterizing the sources of moisture, as well as circulation patterns and relative influences of tropical and midlatitude systems. A conceptual model of the evolution of the premonsoon period is presented.The meridional and temporal variability of surface moisture during the spring is modulated by multiscale interactions, as illustrated for the period from mid-April to early May 2009. As westward-propagating, synoptic disturbances move across West Africa, a corresponding peak occurs in the surface relative humidity. With the passage of each disturbance a new and more humid regime is established. Filtered anomalies of outgoing longwave radiation (OLR) indicate that Kelvin waves, equatorial Rossby waves, and possibly the MJO contributed to the initiation and intensification of the synoptic disturbances. During the last of the disturbances, whose passage raised the relative humidity above 40%, a critical threshold for meningitis, an extratropical cyclone also contributed to moisture influx over the Sahel. Analysis of the period 2000–09 shows the relative influences of synoptic and subseasonal circulations on the onset of high relative humidity over the Sahel during the spring.}, number={9}, journal={Monthly Weather Review}, publisher={American Meteorological Society}, author={Mera, Roberto and Laing, Arlene G. and Semazzi, Frederick}, year={2014}, month={Sep}, pages={3178–3198} } @article{pandya_hodgson_hayden_akweongo_hopson_forgor_yoksas_dalaba_dukic_mera_et al._2015, title={Using Weather Forecasts to Help Manage Meningitis in the West African Sahel}, volume={96}, ISSN={0003-0007 1520-0477}, url={http://dx.doi.org/10.1175/bams-d-13-00121.1}, DOI={10.1175/bams-d-13-00121.1}, abstractNote={Abstract Understanding and acting on the link between weather and meningitis in the Sahel could help improve vaccine distribution and save lives. People living there know that meningitis epidemics occur in the dry season and end after the start of the rainy season. Integrating and analyzing newly available epidemiological and meteorological data quantified this relationship, showing that that the risk of meningitis epidemics climbed from a background level of 2% to a maximum risk of 25% during the dry season. These data also suggested that, of all meteorological variables, relative humidity has the strongest correlation to cases of meningitis. Weather acts alongside a complex set of environmental, social, and economic drivers, and a complementary investigation of local and regional knowledge, attitudes, and practices suggested several additional interventions to manage meningitis. These include improved awareness of early meningitis symptoms and vaccinations for farmworkers who migrate seasonally. An economic survey showed that the cost of a single case of meningitis is 3 times the average annual household income, underscoring the need for improved vaccination strategy. Using these insights, meteorologists and public health workers developed a tool to guide vaccination decisions. Iterative development allowed a multinational team of public health officials to use the tool while guiding its refinement and directed research toward maximum practical use. That meant focusing on predicting areas where high humidity would naturally end epidemics so vaccines could be moved elsewhere. Using this tool and this approach could have prevented an estimated 24,000 cases of meningitis over a 3-yr period.}, number={1}, journal={Bulletin of the American Meteorological Society}, publisher={American Meteorological Society}, author={Pandya, Rajul and Hodgson, Abraham and Hayden, Mary H. and Akweongo, Patricia and Hopson, Thomas and Forgor, Abudulai Adams and Yoksas, Tom and Dalaba, Maxwell Ayindenaba and Dukic, Vanja and Mera, Roberto and et al.}, year={2015}, month={Jan}, pages={103–115} } @inproceedings{mera_allen_dalton_ekwurzel_frumhoff_heede_2013, title={Attributing Rise in Global Average Temperature to Emissions Traceable to Major Industrial Carbon Producer}, author={Mera, Roberto J. and Allen, M.R. and Dalton, M. and Ekwurzel, B. and Frumhoff, P.C. and Heede, R.}, year={2013} } @inproceedings{mera_mote_2011, title={Analysis of Extreme Events in Regional Climate Model Simulations for the Pacific Northwest using weatherathome}, author={Mera, Roberto J. and Mote, P.}, year={2011} } @inproceedings{mera_mote_2011, title={Application of Regional Climate Model Information for Climate Change Hazards Mapping over Oregon}, author={Mera, Roberto J. and Mote, P.}, year={2011} } @inbook{niyogi_mera_xue_wilkerson_booker_2011, place={Cambridge}, title={The use of the Alpert–Stein Factor Separation Methodology for climate variable interaction studies in hydrological land surface models and crop yield models}, ISBN={9780511921414}, url={http://dx.doi.org/10.1017/cbo9780511921414.013}, DOI={10.1017/cbo9780511921414.013}, abstractNote={Author(s): Niyogi, D; Mera, R; Xue, Y; Wilkerson, G; Booker, F | Abstract: © Cambridge University Press, 2011. The Alpert–Stein Factor Separation Methodology (FS) method has been utilized in the study of the biophysical response to changes in the environment to assess the relative contribution of different atmospheric factors to the biological system. In this chapter we will discuss crop simulation and land surface model-based assessments of the sensitivity to past and future changes in climatic conditions: increasing CO2, soil moisture, temperature and radiative conditions, and crop management procedures (irrigation). FS is applied to discern specific contributions to plant responses by single variables or combinations of environmental conditions. Our FS analysis has shown that it is important to understand that biological responses are inherently dependent on multiple variables in the natural world and should not be limited to assessments of single specific parameters. Introduction In this chapter we demonstrate how the FS analysis technique is a useful tool for crop–climate change (crop-clim) studies. Important interactions between the atmosphere and biophysical processes occur under land surface and atmospheric carbon dioxide (CO2) level changes. We employ the Alpert–Stein FS Methodology (Stein and Alpert, 1993; Alpert, 1997) to investigate the direct as well as the interactive effects of soil moisture, temperature, and radiative changes on the direct effects of CO2 doubling for different land-use/vegetation types, including agricultural production.}, booktitle={Factor Separation in the Atmosphere: Applications and Future Prospects}, publisher={Cambridge University Press}, author={Niyogi, D. and Mera, R. and Xue, Yongkang and Wilkerson, G. and Booker, F.}, editor={Alpert, Pinhas and Sholokhman, TatianaEditors}, year={2011}, month={May}, pages={171–183} } @inproceedings{mera_semazzi_2010, title={Investigation of the Interactions among Transient Atmospheric Wave Disturbances over West Africa During Boreal Spring of 2009}, author={Mera, Roberto J. and Semazzi, F.H.M.}, year={2010} } @inproceedings{mera_semazzi_2010, title={Predictability of the Moisture Regime During the Preonset Period of Sahelian Rains}, author={Mera, Roberto J. and Semazzi, F.H.M.}, year={2010} } @inproceedings{mera_semazzi_laing_2010, title={Variability of Atmospheric Moisture during the Boreal Spring in West Africa}, author={Mera, Roberto J. and Semazzi, F.H.M. and Laing, Arlene}, year={2010} } @inproceedings{mera_semazzi_2009, title={Application of WRF to investigate the moisture regime associated with the pre-onset of Sahelian rains}, author={Mera, Roberto J. and Semazzi, F.H.M.}, year={2009} } @inproceedings{mera_semazzi_2009, title={Predictability of the Moisture Regime During the Pre-onset Period of Sahelian Rains}, author={Mera, Roberto J. and Semazzi, F.H.M.}, year={2009} } @inproceedings{pandya_adams-forgor_columbini_hayden_hodgson_hopson_lamptey_lazo_mera_rice_et al._2009, title={Short-term weather forecasts to help allocate meningitis vaccine}, author={Pandya, R. and Adams-Forgor, A. and Columbini, A. and Hayden, M. and Hodgson, A. and Hopson, T. and Lamptey, B. and Lazo, J. and Mera, Roberto J. and Rice, J. and et al.}, year={2009} } @inproceedings{mera_semazzi_2008, title={An Extended Procedure for the RelativeOperating Characteristics Graphical Method}, author={Mera, Roberto J. and Semazzi, F.H.M.}, year={2008} } @article{semazzi_mera_2006, title={An extended procedure for implementing the relative operating characteristic graphical method}, volume={45}, ISSN={["1558-8432"]}, DOI={10.1175/JAM2397.1}, abstractNote={Abstract The functional relationship between the relative operating characteristic (ROC) and the economic value (EV) graphical methods have been exploited to develop a hybrid procedure called the extended ROC (EROC) method. The EROC retains the appealing simplicity of the traditional ROC method and the ability of the EV method to provide evaluation of the performance of an ensemble climate prediction system (EPS) for a hypothetical end user defined by the cost–loss ratio (μ = C/L). An inequality defining the lower and upper theoretical bounds of μ has been derived. Outside these limits, the EPS yields no added benefits for end user μ relative to the use of climatological persistence as an alternative prediction system. In the traditional ROC graphical method, the ROC skill (ROCS) is often expressed in terms of the area between the ROC graph and the diagonal baseline passing through the origin with slope m = 1. Thus, ROCS = 2A − 1, where A is the area under the ROC graph. In the proposed EROC approach, a more general procedure is recommended based on the construction of user-specific baselines that do not necessarily pass through the origin and, in general, have slope m ≠ 1. The skill of a particular EPS computed from the EROC method is proportional to the corresponding estimated value based on the EV graphical method. Therefore, the EROC geometry conveys the same basic information as the EV method. The Semazzi–Mera skill score (SMSS) is proposed as a convenient and compact way of expressing the combined verification based on the ROC and EV methods. The ROCS estimate is a special case of the SMSS. The near-horizontal trail-like geometry sometimes exhibited by EV graphs is also examined. It is shown to occur when either the hit-rate or false-alarm term dominates in the formula for EV, unlike the more typical situation in which both terms are comparable in magnitude.}, number={9}, journal={JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY}, author={Semazzi, Fredrick H. M. and Mera, Roberto J.}, year={2006}, month={Sep}, pages={1215–1223} } @article{mera_niyogi_buol_wilkerson_semazzi_2006, title={Potential individual versus simultaneous climate change effects on soybean (C-3) and maize (C-4) crops: An agrotechnology model based study}, volume={54}, ISSN={["1872-6364"]}, DOI={10.1016/j.gloplacha.2005.11.003}, abstractNote={Landuse/landcover change induced effects on regional weather and climate patterns and the associated plant response or agricultural productivity are coupled processes. Some of the basic responses to climate change can be detected via changes in radiation (R), precipitation (P), and temperature (T). Past studies indicate that each of these three variables can affect LCLUC response and the agricultural productivity. This study seeks to address the following question: What is the effect of individual versus simultaneous changes in R, P, and T on plant response such as crop yields in a C3 and a C4 plant? This question is addressed by conducting model experiments for soybean (C3) and maize (C4) crops using the DSSAT: Decision Support System for Agrotechnology Transfer, CROPGRO (soybean), and CERES-Maize (maize) models. These models were configured over an agricultural experiment station in Clayton, NC [35.65°N, 78.5°W]. Observed weather and field conditions corresponding to 1998 were used as the control. In the first set of experiments, the CROPGRO (soybean) and CERES-Maize (maize) responses to individual changes in R and P (25%, 50%, 75%, 150%) and T (± 1, ± 2 °C) with respect to control were studied. In the second set, R, P, and T were simultaneously changed by 50%, 150%, and ± 2 °C, and the interactions and direct effects of individual versus simultaneous variable changes were analyzed. For the model setting and the prescribed environmental changes, results from the first set of experiments indicate: (i) precipitation changes were most sensitive and directly affected yield and water loss due to evapotranspiration; (ii) radiation changes had a non-linear effect and were not as prominent as precipitation changes; (iii) temperature had a limited impact and the response was non-linear; (iv) soybeans and maize responded differently for R, P, and T, with maize being more sensitive. The results from the second set of experiments indicate that simultaneous change analyses do not necessarily agree with those from individual changes, particularly for temperature changes. Our analysis indicates that for the changing climate, precipitation (hydrological), temperature, and radiative feedbacks show a non-linear effect on yield. Study results also indicate that for studying the feedback between the land surface and the atmospheric changes, (i) there is a need for performing simultaneous parameter changes in the response assessment of cropping patterns and crop yield based on ensembles of projected climate change, and (ii) C3 crops are generally considered more sensitive than C4; however, the temperature–radiation related changes shown in this study also effected significant changes in C4 crops. Future studies assessing LCLUC impacts, including those from agricultural cropping patterns and other LCULC–climate couplings, should advance beyond the sensitivity mode and consider multivariable, ensemble approaches to identify the vulnerability and feedbacks in estimating climate-related impacts.}, number={1-2}, journal={GLOBAL AND PLANETARY CHANGE}, author={Mera, Roberto J. and Niyogi, Dev and Buol, Gregory S. and Wilkerson, Gail G. and Semazzi, Fredrick H. M.}, year={2006}, month={Nov}, pages={163–182} } @inproceedings{mera_niyogi_semazzi_2005, title={Value-based Ensemble Analysis and Potential Individual Versus Simultaneous Climate Change Effects on Agriculture}, author={Mera, Roberto and Niyogi, D. and Semazzi, F.H.M.}, year={2005} }