Search

Numerous circulation indices have been applied in practical climate services focused on regional precipitation. It is beneficial to identify the most influential or decisive indices, but this is difficult with conventional correlation analyses because of the underlying nonlinear mechanisms for precipitation. This paper demonstrates a set of the most influential indices for July–August precipitation in North China, based on the recursive random forest (RRF) method. These decisive circulation indices include the Polar–Eurasia teleconnection, North African subtropical high ridge position, India–Burma trough, Antarctic Oscillation, Northern Hemisphere polar vortex central latitude, North Atlantic Oscillation, and western Pacific subtropical high northern boundary position. Some of these factors have been recognized as directly influential to the regional precipitation, for example, those of the northwestern Pacific subtropical high; however, some are not easily understood. Decision tree (DT) models using these indices were developed to facilitate composite analyses to explain the RRF results. Taking one of the most interesting DT rules as an example, when the North African subtropical high ridge position is sufficiently far south, an anomalous anticyclone occurs in the upstream and an anomalous cyclone in the downstream of North China. This is unfavorable for northward moisture transport in eastern China and hence causes less precipitation in North China than climatology. The present results are not only helpful for improving diagnostic models of regional precipitation, but also enlightening for exploring how global climate change could impact a region by modulating large-scale circulation patterns. [ABSTRACT FROM AUTHOR]

In the past few decades, there have been more extreme climate events occurring worldwide, including Canada, which has also suffered from many extreme precipitation events. In this paper, trend analysis, probability distribution functions, principal component analysis, and wavelet analysis were used to investigate the spatial and temporal patterns of extreme precipitation events of Canada. Ten extreme precipitation indices were calculated using long-term daily precipitation data (1950–2012) from 164 Canadian gauging stations. Several large-scale climate patterns such as El Niño–Southern Oscillation (ENSO), Pacific decadal oscillation (PDO), Pacific–North American (PNA), and North Atlantic Oscillation (NAO) were selected to analyze the relationships between extreme precipitation and climate indices. Convective available potential energy (CAPE), specific humidity, and surface temperature were employed to investigate potential causes of trends in extreme precipitation. The results reveal statistically significant positive trends for most extreme precipitation indices, which means that extreme precipitation of Canada has generally become more severe since the mid-twentieth century. The majority of indices display more increasing trends along the southern border of Canada while decreasing trends dominated the central Canadian Prairies. In addition, strong teleconnections are found between extreme precipitation and climate indices, but the effects of climate patterns differ from region to region. Furthermore, complex interactions of climate patterns with synoptic atmospheric circulations can also affect precipitation variability, and changes to the summer and winter extreme precipitation could be explained more by the thermodynamic impact and the combined thermodynamic and dynamic effects, respectively. The seasonal CAPE, specific humidity, and temperature are correlated to Canadian extreme precipitation, but the correlations are season dependent, which could be positive or negative. [ABSTRACT FROM AUTHOR]

This paper investigates how atmospheric circulation and orography affect the spatial variability of extreme precipitation in terms of depth-duration-frequency (DDF) curve parameters. To this aim, the Italian territory was considered because it is characterized by a complex orography and different precipitation dynamics and regimes. A database of 1494 time series with more than 20 years of maximum annual precipitation data was collected for the durations of 1, 3, 6, 12, and 24 h. For each data series, the parameters of DDF curves were estimated using a statistical simple scale invariance model. Hence, the combined effect of orography and atmospheric fields on parameter variability was investigated considering the spatial distribution of the parameters and their relation with elevation. The vertically integrated atmospheric moisture flux J was used as a measurement of the principal direction of the vapor transport at a given location. The analysis highlights the variability of DDF parameters and quantiles according to orography and precipitation climatology. This is confirmed by the evaluation of J modal direction over the study area. The variability of DDF parameters with mere elevation shows that maxima at high elevations seem to be upper bounded and more variable than those at lower elevations. Moreover, the mean of maximum annual precipitation of unit duration decreases with elevation. This last phenomenon is defined as 'reverse orographic effect' on extreme precipitation of short durations. [ABSTRACT FROM AUTHOR]

This paper analyzes the ability of the North American Regional Climate Change Assessment Program (NARCCAP) ensemble of regional climate models to simulate extreme monthly precipitation and its supporting circulation for regions of North America, comparing 18 years of simulations driven by the National Centers for Environmental Prediction (NCEP)--Department of Energy (DOE) reanalysis with observations. The analysis focuses on the wettest 10%% of months during the cold half of the year (October--March), when it is assumed that resolved synoptic circulation governs precipitation. For a coastal California region where the precipitation is largely topographic, the models individually and collectively replicate well the monthly frequency of extremes, the amount of extreme precipitation, and the 500-hPa circulation anomaly associated with the extremes. The models also replicate very well the statistics of the interannual variability of occurrences of extremes. For an interior region containing the upper Mississippi River basin, where precipitation is more dependent on internally generated storms, the models agree with observations in both monthly frequency and magnitude, although not as closely as for coastal California. In addition, simulated circulation anomalies for extreme months are similar to those in observations. Each region has important seasonally varying precipitation processes that govern the occurrence of extremes in the observations, and the models appear to replicate well those variations. [ABSTRACT FROM AUTHOR]

Orographic precipitation gradients (OPG) relating to the increase or decrease in precipitation amount with elevation are not well studied or analyzed except for case examples. A quality controlled daily OPG dataset for the western United States that is based on a linear regression framework of gauge precipitation observations and elevation for a 39-yr time period was created and analyzed to identify spatial and temporal patterns and variability in OPG and some of the drivers of variability on seasonal, annual, interannual, and climatological time scales. Most locations in the western United States experience positive OPG during most of the year, exhibiting an annual cycle with the highest magnitude of OPG in the winter season and lowest magnitude of OPG in the summer season. Coastal locations tend to have OPG with higher magnitude and larger variability in OPG than do interior locations during cool seasons. Empirical orthogonal function analysis identifies two principal components that account for 33% of the variability in a subset of the OPG dataset, and these modes of variability are related to precipitation amount and atmospheric circulation over the Pacific Ocean. Comparison of daily OPG with similarly calculated 3-day and monthly OPG identifies that OPG magnitudes are sensitive to the choice of length of the precipitation accumulation period. [ABSTRACT FROM AUTHOR]

This study examines space-time patterns of summer daily rainfall variability across the Northeast United States, with a focus on historical trends and the potential for long-lead predictability. Ahidden Markov model based on daily data is used to define six weather states that represent distinct patterns of rainfall across the region, and composites are used to examine atmospheric circulation during each state. The states represent the occurrence of region-wide dry and wet conditions associated with a large-scale ridge and trough over the Northeast, respectively, as well as inland and coastal storm tracks. There is a positive trend in the frequency of the weather state associated with heavy, regionwide rainfall, which is mirrored by a decreasing trend in the frequency of stationary ridges and regionwide dry conditions. The frequency of state occurrences is also examined for historical Northeast droughts. Two primary drought types emerge that are characterized by region-wide dry conditions linked to a persistent ridge and an eastward-shifted storm track associated with light precipitation along the coastline. Finally, composites of May sea surface temperature anomalies (SSTAs) prior to summers with high and low frequencies of each weather state are used to assess long-lead predictability. These composites are compared against similar composites based on regional anomalies in low streamflow conditions [June-August 7-day low flows (SDLFs)]. Results indicate that springtime SSTs, particularly those in the Caribbean Sea and tropical North Atlantic Ocean, provide some predictability for summers with above-average precipitation and SDLFs, but SSTs provide little information on the occurrence of drought conditions across the Northeast. [ABSTRACT FROM AUTHOR]

This study investigated atmospheric water cycles over several time scales to understand the maintenance processes that control heavy precipitation over the islands of the Maritime Continent. Large island regions can be divided into land, coastal, and ocean areas based on the characteristics of both the hydrologic cycle and the diurnal variation in precipitation. Within the Maritime Continent, the major islands of Borneo and New Guinea exhibit different hydrologic cycles. Large-scale circulation variations, such as the seasonal cycle and the Madden–Julian oscillation, have a lesser effect on the hydrologic cycle over Borneo than over New Guinea because the effects depend on their shapes and locations. The impact of diurnal variations on both regional-scale circulation and water exchange between land and coastal regions is pronounced over both islands. The recycling ratio of precipitation, which can be related to stronger diurnal variation in the atmospheric water cycle that results from enhanced evapotranspiration over tropical rain forests, is higher over Borneo than over New Guinea. [ABSTRACT FROM AUTHOR]

The top 100 basin-scale 1-day precipitation, multiday precipitation, and 1-day streamflow events from 1950 to 2012 are examined for the Ashokan reservoir, a key water source for New York City. Through a cyclone association algorithm, extratropical cyclones (ETCs) are found to be associated with the majority of the top 100 precipitation and streamflow events. Tropical cyclones (TCs) generate the second-most top 100 one-day and multiday precipitation events, with more than two-thirds of these TCs having undergone extratropical transition. Furthermore, TCs that pass over the region are approximately 7 and 4 times more likely to generate a top 100 one-day precipitation and one-day streamflow event, respectively, than ETCs. Lagrangian cyclone track analysis shows cool season ETCs take a more meridional path compared to warm season ETCs. A composite analysis shows that for the top 100 one-day precipitation events, ETCs have relatively less moisture but stronger upper-level support than TCs. Due in part to TCs, heavy precipitation events occur more often in the warm season, whereas high streamflow events occur mainly in the cool season. Despite this difference, approximately 43% of the top 100 events, which represent many of the very strongest events, overlap for all three metrics. While high temperature and specific humidity anomalies accompany all top 100 events, the magnitude of the anomalies is greatest for isolated streamflow events. This analysis provides a reference to forecasters and water managers regarding the relative and synoptic-scale behavior of different storm types for isolated and concurrent precipitation and streamflow events. [ABSTRACT FROM AUTHOR]

Rainfall in the Levant drylands is scarce but can potentially generate high-magnitude flash floods. Rainstorms are caused by distinct synoptic-scale circulation patterns: Mediterranean cyclone (MC), active Red Sea trough (ARST), and subtropical jet stream (STJ) disturbances, also termed tropical plumes (TPs). The unique spatiotemporal characteristics of rainstorms and floods for each circulation pattern were identified. Meteorological reanalyses, quantitative precipitation estimates from weather radars, hydrological data, and indicators of geomorphic changes from remote sensing imagery were used to characterize the chain of hydrometeorological processes leading to distinct flood patterns in the region. Significant differences in the hydrometeorology of these three flood-producing synoptic systems were identified: MC storms draw moisture from the Mediterranean and generate moderate rainfall in the northern part of the region. ARST and TP storms transfer large amounts of moisture from the south, which is converted to rainfall in the hyperarid southernmost parts of the Levant. ARST rainfall is local and intense, whereas TP rainfall is widespread and prolonged due to high precipitation efficiency and large-scale forcing. Thus, TP rainfall generates high-magnitude floods in the largest catchments; integration of numerous basins leads to sediment feeding from the south into the Dead Sea, exhibited in large sediment plumes. Anecdotal observations of the channel with the largest catchment in the region (Nahal HaArava) indicate that TP floods account for noticeable geomorphic changes in the channel. It provides insights into past intervals of increased flash flood frequency characterized by episodes of marked hydrogeomorphic work; such an increase is especially expected during intervals of southerly situated and southwesterly oriented STJs. [ABSTRACT FROM AUTHOR]

The 2013 federal Colorado River Basin Water Supply and Demand Study projected the water imbalance between future supply and demand to increase. The Colorado water supply (WS) exemplifies a pronounced quasi-decadal oscillation (QDO) of 10-20 years throughout its historical record; however, this QDO feature is unaccounted for in the climate models used to project the future WS. Adjacent to the Colorado River, the large watershed of the Great Salt Lake (GSL) in Utah records the hydrologicQDOsignal in its water surface, leading previous studies to explore the cause of decadal fluctuations in the lake elevation and assess predictability. This study reports a remarkable coherence between the Colorado WS and the GSL elevation at the 10-20-yr time scale. Analysis of precipitation and terrestrial water storage anomalies suggests a crossbasin connection in the climate and hydrometeorological variations of the Colorado WS and the GSL. The 160-yr-long and well-kept GSL elevation record makes it an effective indicator for the Colorado WS. [ABSTRACT FROM AUTHOR]

Two extreme, high-impact events of heavy rainfall and severe floods in West African urban areas (Ouagadougou on 1 September 2009 and Dakar on 26 August 2012) are investigated with respect to their atmospheric causes and statistical return periods. In terms of the synoptic–convective dynamics, the Ouagadougou case is truly extraordinary. A succession of two slow-moving African easterly waves (AEWs) caused record-breaking values of tropospheric moisture. The second AEW, one of the strongest in recent decades, provided the synoptic forcing for the nighttime genesis of mesoscale convective systems (MCSs). Ouagadougou was hit by two MCSs within 6 h, as the strong convergence and rotation in the AEW-related vortex allowed a swift moisture refueling. An AEW was also instrumental in the overnight development of MCSs in the Dakar case, but neither the AEW vortex nor the tropospheric moisture content was as exceptional as in the Ouagadougou case. Tropical Rainfall Measuring Mission (TRMM) 3B42 precipitation data show some promise in estimating centennial return values (RVs) using the "peak over threshold" approach with a generalized Pareto distribution fit, although indications for errors in estimating extreme rainfall over the arid Sahel are found. In contrast, the Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks–Climate Data Record (PERSIANN-CDR) dataset seems less suitable for this purpose despite the longer record. Notably, the Ouagadougou event demonstrates that highly unusual dynamical developments can create extremes well outside of RV estimates from century-long rainfall observations. Future research will investigate whether such developments may become more frequent in a warmer climate. [ABSTRACT FROM AUTHOR]

The purpose of this study is to use the PERSIANN-Climate Data Record (PERSIANN-CDR) dataset to evaluate the ability of 32 CMIP5 models in capturing the behavior of daily extreme precipitation estimates globally. The daily long-term historical global PERSIANN-CDR allows for a global investigation of eight precipitation indices that is unattainable with other datasets. Quantitative comparisons against CPC daily gauge; GPCP One-Degree Daily (GPCP1DD); and TRMM 3B42, version 7 (3B42V7), datasets show the credibility of PERSIANN-CDR to be used as the reference data for global evaluation of CMIP5 models. This work uniquely defines different study regions by partitioning global land areas into 25 groups based on continent and climate zone type. Results show that model performance in warm temperate and equatorial regions in capturing daily extreme precipitation behavior is largely mixed in terms of index RMSE and correlation, suggesting that these regions may benefit from weighted model averaging schemes or model selection as opposed to simple model averaging. The three driest climate regions (snow, polar, and arid) exhibit high correlations and low RMSE values when compared against PERSIANN-CDR estimates, with the exceptions of the cold regions showing an inability to capture the 95th and 99th percentile annual total precipitation characteristics. A comprehensive assessment of each model's performance in each continent-climate zone defined group is provided as a guide for both model developers to target regions and processes that are not yet fully captured in certain climate types, and for climate model output users to be able to select the models and/or the study areas that may best fit their applications of interest. [ABSTRACT FROM AUTHOR]

Aircraft dropsonde observations provide the most comprehensive measurements to date of horizontal water vapor transport in atmospheric rivers (ARs). The CalWater experiment recently more than tripled the number of ARs probed with the required measurements. This study uses vertical profiles of water vapor, wind, and pressure obtained from 304 dropsondes across 21 ARs. On average, total water vapor transport (TIVT) in an AR was 4.7 × 108 ± 2 × 108 kg s−1. This magnitude is 2.6 times larger than the average discharge of liquid water from the Amazon River. The mean AR width was 890 ± 270 km. Subtropical ARs contained larger integrated water vapor (IWV) but weaker winds than midlatitude ARs, although average TIVTs were nearly the same. Mean TIVTs calculated by defining the lateral 'edges' of ARs using an IVT threshold versus an IWV threshold produced results that differed by less than 10% across all cases, but did vary between the midlatitudes and subtropical regions. [ABSTRACT FROM AUTHOR]

Tropical moisture exports (TMEs) may play an important role in extreme precipitation. An analysis of the spatiotemporal structure of precipitation associated with TMEs for the eastern United States at seasonal and daily time scales is presented. TME-based precipitation is characterized based on the change in specific humidity along TME tracks delineated in a Lagrangian analysis of the ERA-Interim dataset. The empirical orthogonal functions (EOFs) of seasonal TME-based precipitation are analyzed separately for each season to identify the dominant modes of interannual variability. Loading patterns for the first EOF show a distinct seasonal cycle in the core region of TME-based precipitation across the eastern United States, while the second EOF describes a northwest-southeast oscillation in the center of TME-induced precipitation occurrence. The EOFs for TMEs are compared against EOFs of gauged flood count data, which exhibit similar spatial structures. Correlations between TME EOFs, geopotential heights, and sea surface temperatures suggest a strong connection between TME-based precipitation, the Pacific-North American (PNA) pattern, Pacific decadal oscillation (PDO), and the Intra-Americas Sea patterns for much of the calendar year. Daily TME-based and total precipitation is projected onto the leading seasonal EOFs to examine the characteristics of upper-quantile daily events. The daily analysis suggests that the PNA can potentially provide information regarding heavy TME-based precipitation at a lead time of 1-10 days or more in most seasons and total precipitation in the winter. The potential for subseasonal, seasonal, and decadal forecasts or conditional simulations of precipitation in the study region is discussed. [ABSTRACT FROM AUTHOR]

The precipitable water (PW) content was estimated over southern Greece for three atmospheric layers, using 28-yr twice-daily radiosonde measurements of temperature, humidity, and atmospheric pressure. Precipitable water demonstrates considerable variation at the monthly and interannual time scales as well as statistically significant upward trends at the annual level and for June–August (JJA) and September–November (SON). The relationship between PW and surface climate was also found to vary by season and surface climate variable. Disaggregation of seasonal PW trends by synoptic type revealed that seasonal trends might be attributed to increases in moisture in a limited number of airmass types such that maritime air masses appear to be becoming moister while their continental counterparts are drying. Despite fundamental changes to the intrinsic PW properties of air masses for some synoptic categories, the significance of these for determining the overall trend in seasonal PW levels is related to their weighted contribution as determined by changing airmass frequency. Consequently, the climatological effects of a moistening or drying air mass may be offset by a declining frequency. It is also shown that increasing PW trends cannot be attributed unequivocally to airmass warming as significant increases in PW have occurred in conjunction with falling temperatures in some seasons and airmass types. Accordingly, factors other than the commonly assumed global-warming-related increase in atmospheric moisture via the link between temperature and saturation vapor pressure must be considered if the mechanisms responsible for PW trends over southern Greece are to be fully understood. [ABSTRACT FROM AUTHOR]

The large-scale atmospheric hydrologic cycle over the United States and Mexico derived from the 23-yr NCEP regional reanalysis (RR) was evaluated by comparing the RR products with satellite estimates, independent sounding data, and the operational Eta Model three-dimensional variational data assimilation (3DVAR) system (EDAS). In general, the winter atmospheric transport and precipitation are realistic. The climatology and interannual variability of the Pacific, subtropical jet streams, and low-tropospheric moisture transport are well captured. During the summer season, the basic features and the evolution of the North American monsoon (NAM) revealed by the RR compare favorably with observations. The RR also captures the out-of-phase relationship of precipitation as well as the moisture flux convergence between the central United States and the Southwest. The RR is able to capture the zonal easterly Caribbean low-level jet (CALLJ) and the meridional southerly Great Plains low-level jet (GPLLJ). Together, they transport copious moisture from the Caribbean to the Gulf of Mexico and from the Gulf of Mexico to the Great Plains, respectively. The RR systematically overestimates the meridional southerly Gulf of California low-level jet (GCLLJ). A comparison with observations suggests that the meridional winds from the RR are too strong, with the largest differences centered over the northern Gulf of California. The strongest winds over the Gulf in the RR extend above 700 hPa, while the operational EDAS and station soundings indicate that the GCLLJ is confined to the boundary layer. [ABSTRACT FROM AUTHOR]

Because precipitation and net radiation in an atmospheric general circulation model (AGCM) are typically biased relative to observations, the simulated evaporative regime of a region may be biased, with consequent negative effects on the AGCM’s ability to translate an initialized soil moisture anomaly into an improved seasonal prediction. These potential problems are investigated through extensive offline analyses with the Mosaic land surface model (LSM). The LSM was first forced globally with a 15-yr observation-based dataset. The simulation was then repeated after imposing a representative set of GCM climate biases onto the forcings—the observational forcings were scaled so that their mean seasonal cycles matched those simulated by the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1; NASA Global Modeling and Assimilation Office) AGCM over the same period. The AGCM’s climate biases do indeed lead to significant biases in evaporative regime in certain regions, with the expected impacts on soil moisture memory time scales. Furthermore, the offline simulations suggest that the biased forcing in the AGCM should contribute to overestimated feedback in certain parts of North America—parts already identified in previous studies as having excessive feedback. The present study thus supports the notion that the reduction of climate biases in the AGCM will lead to more appropriate translations of soil moisture initialization into seasonal prediction skill. [ABSTRACT FROM AUTHOR]

In this study, the authors focused on the seasonal variations of precipitation properties over the western Pacific, particularly those associated with the wind direction of the monsoon. An observational project over Peleliu Island in the Republic of Palau was carried out, and data on precipitation, equivalent cloud amount, and precipitable water were collected from 28 June 2001 to 30 April 2002. First, the monsoon season over Palau was defined as a period with 850-hPa zonal-wind sounding data with sustained winds exceeding 5 m s-1. The westerly wind regime continued until 25 November 2001, and the next westerly wind regime began on 18 May 2002. The equivalent cloud amount increased during the period when the westerly wind intensified. The precipitation had a diurnal variation in the active phase of the westerly wind regime, increasing from nighttime to early morning and decreasing in the afternoon. The diurnal variation was weak in the inactive phase and had a lesser afternoon maximum. Precipitation intensity was high and its duration was short during the westerly wind regime. The precipitable water decreased during the easterly wind regime when a dry period appeared, and precipitation was also suppressed during those days. However, there was little difference between the precipitation amounts of the westerly and easterly wind regimes. The equivalent cloud amount did not decrease as the zonal-wind direction changed to easterlies during the easterly wind regime. The authors noticed no diurnal variation of precipitation during the easterly wind regime. These differences in the precipitation properties during westerlies and easterlies may be related to the seasonal variation of humidity in the environment. [ABSTRACT FROM AUTHOR]

The extent to which winter precipitation is orographically enhanced within the Sierra Nevada of California varies from storm to storm, and season to season, from occasions when precipitation rates at low and high altitudes are almost the same to instances when precipitation rates at middle elevations (considered here) can be as much as 30 times more than at the base of the range. Analyses of large-scale conditions associated with orographic precipitation variations during storms and seasons from 1954 to 1999 show that strongly orographic storms most commonly have winds that transport water vapor across the range from a more nearly westerly direction than during less orographic storms and than during the largest overall storms, and generally the strongly orographic storms are less convectively stable. Strongly orographic conditions often follow heavy precipitation events because both of these wind conditions are present in midlatitude cyclones that form the cores of many Sierra Nevada storms. Storms during La Niña winters tend to yield larger orographic ratios (ORs) than do those during El Niños. A simple experiment with a model of streamflows from a river basin draining the central Sierra Nevada indicates that, for a fixed overall basin-precipitation amount, a decrease in OR contributes to larger winter flood peaks and smaller springtime flows, and thus to an overall hastening of the runoff season. [ABSTRACT FROM AUTHOR]

A series of atmospheric general circulation model simulations, spanning a total of several thousand years, is used to assess the impact of land surface and ocean boundary conditions on the seasonal-to-interannual variability and predictability of precipitation in a coupled modeling system. In the first half of the analysis, which focuses on precipitation variance, the contributions of ocean, atmosphere, and land processes to this variance are characterized, to first order, with a simple linear model. The resulting clean separation of the contributions leads to two results: 1) land and ocean processes have essentially different domains of influence, that is, the amplification of precipitation variance by land-atmosphere feedback is most important outside of the regions (mainly in the Tropics) that are most affected by sea surface temperatures; and 2) the strength of land-atmosphere feedback in a given region is controlled largely by the relative availability of energy and water there. In the second half of the analysis, the potential for seasonal-to-interannual predictability of precipitation is quantified under the assumption that all relevant surface boundary conditions (in the ocean and on land) are themselves perfectly predictable. Although the chaotic nature of the atmospheric circulation imposes fundamental limits on precipitation predictability in many regions, foreknowledge of sea surface temperature contributes significantly to predictability in the Tropics, and foreknowledge of land surface moisture state contributes significantly to predictability in transition zones between dry and humid climates. Thus, soil moisture initialization or assimilation in a seasonal-to-interannual forecasting system would be especially beneficial in these transition zones. [ABSTRACT FROM AUTHOR]