Northwest Subregion Research Articles

On-Orbit Response Characteristics of Fengyun-4A Lightning Mapping Imager (LMI) and Their Impacts on LMI Detection

Abstract The effects of the response characteristics of the Fengyun-4A Lightning Mapping Imager (LMI) on its detection capability were studied using the raw event data of LMI in 2020. The simultaneous observation data of the Lightning Imaging Sensor (LIS) on the International Space Station (ISS) were used to evaluate the LMI detection capability. The results reveal that the minimum detectable radiance of lightning events in the 16 subregions of LMI has shown regional differences, with the southern subregions lower than the northern subregions, indicating that the southern ones are more conducive to the identification of events. The diurnal variation of the detectable event radiance in all subregions presents the main peak around noon, which comes from the influence of the bright background and varies largely in different subregions depending on the subregions’ response capability. The overall high values and regional differences of flash properties observed by LMI also show strong correlation with the variation of the minimum detectable radiance of events. Moreover, it is found that the southwest subregions have the highest coincidence ratio (CR) with ISS LIS, followed by the southeast subregions and the northeast subregions, and the northwest subregions have the lowest CR, which is closely related to the response of each subregion. The LIS flashes that can be detected by LMI are brighter, larger, and last longer compared to the total LIS flashes. The findings in this study will help explain the inconsistency of the LMI detection capability and promote the LMI data processing associated with pixel energy distribution. Significance Statement The Fengyun-4A (FY-4A) Lightning Mapping Imager (LMI) is the first geostationary satellite-borne lightning imager developed in China, which has the ability to continuously observe lightning within a large field of view. However, in the application of the data, it was found that the detection capability of the LMI differed significantly in different regions and exhibited diurnal variations, which may be related to the response characteristics of the LMI detector. This study reveals the effect of the response characteristics of the LMI detector on its detection results. The findings will help improve the usability of LMI data and improve the processing of these data to adjust the observation inconsistency.

Quinolone distribution, trophodynamics, and human exposure risk in a transit-station lake for water diversion in east China

Quinolone antibiotics (QNs) pollution in lake environments is increasingly raising public concern due to their potential combined toxicity and associated risks. However, the spatiotemporal distribution and trophodynamics of QNs in transit-station lakes for water diversion are not well documented or understood. In this study, a comprehensive investigation of QNs in water, sediment, and aquatic fauna, including norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), and ofloxacin (OFL), was conducted in Luoma Lake, a major transit station for the eastern route of the South-to-North Water Diversion Project in China. The target QNs were widely distributed in the water (∑QNs: 70.12 ± 62.79 ng/L) and sediment samples (∑QNs: 13.35 ± 10.78 ng/g dw) in both the non-diversion period (NDP) and the diversion period (DP), where NOR and ENR were predominant. All the QNs were detected in all biotic samples in DP (∑QNs: 80.04 ± 20.59 ng/g dw). The concentration of ∑QNs in the water in NDP was significantly higher than those in DP, whereas the concentration in the sediments in NDP was comparable to those in DP. ∑QNs in the water-sediment system exhibited decreasing trends from northwest (NW) to southeast (SE) in both periods; however, the Koc (organic carbon normalized partition coefficients) of individual QNs in DP sharply rose compared with those in NDP, which indicated that water diversion would alter the environmental fate of QNs in Luoma Lake. In DP, all QNs, excluding NOR, were all biodiluted across the food web; whereas their bioaccumulation potentials in the SE subregion were higher than those in the NW subregion, which was in contrast to the spatial distribution of their exposure concentrations. The estimated daily QN intakes via drinking water and aquatic products suggested that residents in the SE side were exposed to greater health risks, despite less aquatic pollution in the region.

Key coastal landscape patterns for reducing flood vulnerability

The purpose of the present study was to examine key coastal landscape patterns related to flood vulnerability to support resilience strategies for coastal green infrastructure. To this end, we assessed the flood vulnerability of coastal landscapes based on three indicators: exposure, including precipitation; sensitivity, including elevation, slope, soil, drainage, and density; and adaptability, including urban land-use. Subsequently, we investigated whether landscape patterns, including the shape index and subdivision index, would affect flood vulnerability through a multivariate regression analysis, which allowed us to determine key coastal landscape patterns. At the regional scale, including the overall study site, we suggested strategies for green infrastructure planning, focusing on patch shapes of forest, grassland, and water. At each local scale, a variety of landscape patterns were selected: the contiguity index of used area for the central subregion: the division index of forests, the contiguity of water, and the fractal dimension index of used area for the northeast subregion; the circumscribing circle index of barren and wetlands for the northwest subregion; the division and fractal index of forests for the southwest subregion; and the division index of forests and the fractal index of water for the southeast subregion. Based on the derived landscape patterns of each subregion, we propose coastal green infrastructure planning with resilience strategies.

Spatiotemporal regionalization of atmospheric dust based on multivariate analysis of MACC model over Iran

Extraordinary dry conditions on the desert and arid areas in Iran, along with strong influences from surrounding dust sources in the Middle East and Arabia, have exposed the country to substantial amounts of dust aerosols with serious impacts on environment, health and socio-economic aspects. Considering this threat, daily aerosol optical depth (AOD) data over Iran obtained from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis during 2003–2012 were used to analyze the spatial and temporal patterns of total AOD (TAOD) and dust AOD (DAOD). This study identifies the areas mostly affected by TAOD and DAOD in terms of daily average values and the areas associated with distinct temporal patterns, utilizing S-mode and T-mode principal component analysis (PCA). The analysis reveals six distinct sub-regions in southeast, west-northwest, northeast, east, central and southwest of Iran, which are among the major centers influenced by TAOD and DAOD extremes. The main findings of the T-mode results, consistent with TAOD and DAOD S-mode patterns, are (i) the maximum dust loading over the eastern, southeastern and southwestern subregions in March and May, (ii) dust loading with peaks in November over the eastern and northeastern sub-regions; (iii) maximum number of dusty days in July and August over southwest, (iv) maximum dust in July over southeastern and Central Iran, (v) a dust pattern with identical extent over the west and northwest sub-region in March and October and, (vi) a prevailing dust loading over the dry areas (Lut desert, Sistan plain and southwest edge of the territory) in October. The spatiotemporal evolution of dust is a function of the growth and expansion of dust extremes originated from various sources in Iran and the Middle East. The PCA methodology, through simplification of aerosol distribution to simpler structures, was also incorporated to provide a geographical interpretation of the highly sensitive territory of Iran.

Future drought characteristics through a multi-model ensemble from CMIP6 over South Asia

To characterize future drought events over a drought prone area like South Asia is paramount for drought risk mitigation. In this paper, a five-model ensemble mean from CMIP6 was chosen to project drought characteristics in South Asia under the latest SSPs-RCPs emission scenarios (SSP1–2.6, SSP2–4.5, and SSP5–8.5) for the period 2020–2099. Additionally, corresponding scenarios RCP2.6, RCP4.5 and RCP8.5 of CMIP5 were used for comparison and to identify the changes and improvements of CMIP6 over the South Asia. Principle Component Analysis and the Varimax rotation method is used to divided the study area into five homogenous drought sub-regions. Drought duration, frequency, and intensity are analyzed based on the Run theory, and the Standardized Precipitation Evapotranspiration Index (SPEI) at 12-months timescale, and the self-calibrating Palmer Drought Severity Index (sc-PDSI). The Modified Mann-Kendall and Sen's slope method is adopted to detect sub-regional trends in drought characteristics. Results show that significant increases in drought conditions mainly pronounced over the North-West sub-region. Strong increases are projected in the average drought duration and drought frequency. The North-West sub-region is the most vulnerable to face frequent drought events with longer duration with higher intensity. Parts of the South-West, North-Central, and North-East sub-regions will also face more adverse drought conditions in future. The selected model ensemble from CMIP6 has a very robust capability to simulate present climate parameters (precipitation, temperature, and evaporation) and satisfactorily captures drought characteristics in South Asia. These results provide a basis for developing drought adaptation measures for South Asia.

Change in the fire season pattern from bimodal to unimodal under climate change: The case of Daxing'anling in Northeast China

The length of the wildfire season has become longer in many regions around the world under climate change. This study investigated changes in fire season pattern (i.e., the number of separate periods of a year when wildfires are most likely to ignite, spread, and affect resources) and the contributions of climate change in Daxing'anling, Northeast China. An expanded fire dataset in both spatial and temporal converge from ground reporting was used. A comparison with satellite detected burned areas showed good agreement in spring, summer, and entire fire season. The results showed that the number of fires used to appear in a bimodal pattern with spring and fall peaks in the last century, but transitioned to a unimodal pattern peaked in summer in this century. This conversion was mainly resulted from a remarkable increase in summer lightning fires, which was in turned associated with warming in Daxing'anling. Another factor for the conversion was decreased spring nonlightning fire occurrence in the northwest subregion, where the conversion was the most significant. This decrease of fire was mainly associated with increased precipitation. The analysis of a compositional fire series, built as the log of the ratio of lightning to nonlightning fires, suggests that climate change was a major factor for the conversion of fire season pattern. The finding from this study indicates a need to adjust the fire prevention implementation timeline by including summer fires and to develop strategies to reduce the related risks to firefighter safety and forest ecosystem health in Daxing'anling.

Analysis of the characteristics and driving forces of water footprint productivity in paddy rice cultivation in China.

Water productivity improvement is fundamental to agricultural water use control, and the water footprint provides a new and comprehensive method for identifying the crop-water relationship. This study is intended to explore the spatiotemporal pattern and driving forces underlying the rice water footprint productivity (WFP) in China during the years 1996-2015 based on calculations of the provincial blue, green, gray, and white water footprints. The national water footprint in paddy rice cultivation was 240.97 Gm3 , and green water accounted for 43.9% of the total. The WFP was 0.795 kg m-3 and increased over time in all 30 provinces for which it was calculated. The growth rate in the northern provinces was greater than that in the southern part of the country. The WFP clustered geographically in all years observed. High-value provinces were concentrated to the south of the Yangtze River, whereas most of the provinces that showed a low WFP were distributed in the north China and northwest subregions. Precipitation and sunshine hours were the most obvious driving factors of rice WFP. The effects of agricultural input, e.g., agricultural machinery power, pesticides, and irrigation efficiency, on WFP also could not be ignored. The WFP is a comprehensive and useful index of the crop-water relationship and water-use efficiency. Improving agricultural input and irrigation technology are reliable approaches for WFP promotion. Areas in northeast China showed the most urgent need for improving the rice WFP, and the inclusion of the main grain producing areas in the Yangtze River Basin will further reduce ineffective water occupancy to improve water-use efficiency. © 2019 Society of Chemical Industry.

Sub-regional CO2 Storage Resource and Containment Assessment of Cambrian and Ordovician Formations in Eastern Ohio

The CO2 storage resources and containment effectiveness of deep Cambrian and Ordovician geologic formations were evaluated in eastern Ohio, USA, to evaluate the potential of geologic carbon storage to act as a greenhouse gas reduction strategy in the northwest sub-region of the Appalachian basin. Data compilation, geologic characterization, and storage reservoir and caprock feasibility assessments were conducted following systematic workflows that are consistent with other widely used and internationally recommended approaches for site screening, site selection, and resource classification. Results of this prospective storage resource assessment suggest there are suitable options for deep saline CO2 storage and containment in select areas of central and east-central Ohio. This study provides the foundation of technical expertise and knowledge required to advance carbon capture and storage in the Appalachian basin region. A continued effort is needed to conduct site-specific characterization and ranking of selected areas to determine qualified sites for CO2 injection in the eastern Ohio study area.

Temporal Trends and Spatial Patterns of Temperature and Its Extremes over the Beijing-Tianjin Sand Source Region (1960–2014), China

In order to examine temperature changes and extremes in the Beijing-Tianjin Sand Source Region (BTSSR), ten extreme temperature indices were selected, categorized, and calculated spanning the period 1960–2014, and the spatiotemporal variability and trends of temperature and extremes on multitimescales in the BTSSR were investigated using the Mann-Kendall (M-K) test, Sen’s slope estimator, and linear regression. Results show that mean temperatures have increased and extreme temperature events have become more frequent. Annual temperature has recorded a significant increasing trend over the BTSSR, in which 51 stations exhibited significant increasing trends (p<0.05); winter temperature recorded the most significant increasing trend in the northwest subregion. All extreme temperature indices showed warming trends at most stations; a higher warming slope in extreme temperature mainly occurred along the northeast border and northwest border and in the central-southern mountain area. As extreme low temperature events decrease, vegetation damage due to freezing temperatures will reduce and low cold-tolerant plants may expand their distribution range northward to revegetate barren areas in the BTSSR. However, in water-limited areas of the BTSSR, increasing temperatures in the growing season may exacerbate stress associated with plants relying on precipitation due to higher temperatures combining with decreasing precipitation.

Influence of two types of ENSO events on tropical cyclones in the western North Pacific during the subsequent year: asymmetric response

The paper examines the relationships between ENSO events and tropical cyclones (TCs) in the western North Pacific (WNP) during the ENSO decaying phase of March to July [MAMJJ(1)]. It is shown that WNP TC response is asymmetric to ENSO warm and cold events during MAMJJ(1), associated with the asymmetric patterns of oceanic and atmospheric environmental variables. Eastern Pacific warm events correspond to a westward shift in TC genesis location and a significant decrease of the TC number in the southwest subregion of the WNP, which is consistent with unfavorable atmospheric and oceanic conditions for TC activity during MAMJJ(1). Correspondingly, there is a much less WNP TC number, a shorter TC duration, and a decreased tendency in all three primary TC tracks. During MAMJJ(1) of eastern Pacific cold events, an increased TC activity in the northeast subregion results in an enhanced TC genesis number in the WNP. Central Pacific ENSO events have little effect on WNP TC activity during MAMJJ(1), except that central Pacific warm events are unfavorable for TCs to form in the northwest subregion associated with atmospheric and oceanic conditions. The paper also compares and discusses the TC response to ENSO events during the ENSO developing year of March–July.

Strategic Planning for Employment Self-Containment in Metropolitan Sub-Regions

Metropolitan strategic plans often focus on strengthening local employment opportunities to address the congestion and commuting issues threatening city sustainability. The success of such strategies relies on a more equitable distribution of jobs between sub-regions and can be comparatively benchmarked through one of the three related measures of employment self-sufficiency, self-containment or jobs-housing balance. However, in practice, planning policy implementation to meet these targets seldom reduces automobile commuting. This paper investigates self-containment across a range of occupation and industry types to highlight large differences in commuting and employment patterns through a case study of Perth’s Northwest sub-region, Western Australia. Its findings suggest the application of current sub-regional policy and targets within Perth may reinforce the wage and skill disadvantage of outer metropolitan sub-regions over the inner core. It recommends a more nuanced understanding of these measures taking into account the complex dynamics of both employment opportunities and commuting patterns across sub-regions of a city.

Trends of temperature and precipitation extremes in the Loess Plateau Region of China, 1961–2010

The spatial and temporal trends of 11 (7) temperature (precipitation) extreme indices are examined for the Loess Plateau Region (LPR) and its southeast and northwest sub-regions based on daily observations at 214 meteorological stations. Results show widespread significant warming trends for all the temperature extremes except for the diurnal temperature range (DTR) and the lowest daily maximum temperature in each year (TXn) during 1961–2010. When regionally averaged, a significant warming trend is detected for all the indices except for DTR and TXn in the past 50 years. Compared with the entire LPR, a significant warming trend is detected for all the indices except for DTR and TXn over the southeast sub-region of LPR; while it is observed for all the indices over the northwest. The trends for these indices are generally stronger in the northwest than in the southeast in the past 50 years. In contrast, for precipitation indices, only a small percentage of areas show significant drying or wetting trends and, when regionally averaged, none of them displays significant trends during the past 50 years. On the sub-regional scale, however, a larger percentage of areas show significant drying trends for precipitation indices generally over the southeast relative to the entire LPR, and noticeably, the sub-regional average heavy precipitation (R10mm) and wet day precipitation (PRCPTOT) display significant decreasing trends during the past 50 years; whereas only a slightly larger percentage of areas show significant wetting trends for these indices over the northwest compared with the entire LPR, and when sub-regionally averaged, none of the indices have significant trends during the past 50 years.

Multiyear monitoring of soil moisture over Iran through satellite and reanalysis soil moisture products

Soil moisture (SM) plays a fundamental role for many hydrological applications including water resources, drought analysis, agriculture, and climate variability and extremes. SM is not measured in most parts of Iran and limited measurements do not meet sufficient temporal and spatial resolution. Hence, due to ease of operation, their global coverage and demonstrated accuracy, use of remote sensing SM products is almost the only way for deriving SM information in Iran. In the present research, surface SM (SSM) datasets at six subregions of Iran with different climate conditions were extracted from two satellite-based passive (SMOSL3) and active+passive (ESA CCI SM) microwave observations, and two reanalysis (ERA-Interim and ERA-Interim/Land) products. Time series of averaged monthly mean SSM products and in situ ground precipitation and temperature measurements were derived for each subregion. Results revealed that, generally, all SSM products were in good agreement with each other with correlation coefficients higher than 0.5. The better agreement was found in the Northeast and Southwest region with average correlation values equal to 0.88 and 0.91, respectively. It should be noted that the SSM datasets are characterized by different periods and lengths. Hence, results should be assessed with cautious. Moreover, most SSM products have strong correlations with maximum, minimum and average temperature as well as with total monthly precipitation. Also, trend analysis showed no trend for time series of monthly SSM over all subregions in the two periods 1980–1999 and 2000–2014. The only exceptions were the Southeast subregion for ERA-Interim and Center and Northwest subregions for the ESA CCI SM for which a negative trend was detected for the period 2000–2014. Finally, the Standardized Soil Moisture Index (SSI) calculated from ERA-Interim, ERA-I/Land and ESA CCI SM datasets showed that the Center and Southeast regions suffered from the most severe and longest-lasting drought events in the last decade.

The Online What if? Planning Support System: A Land Suitability Application in Western Australia

Recent advances in cloud computing and the ability to more easily deliver online tools and services provide exciting opportunities for the development and application of online planning support systems. This paper describes the application of an online open source land suitability tool which has been developed as one of the many tools available through the Australian Urban Research Infrastructure Network (AURIN) workbench. The tool is part of the larger open source online What if? planning support system (PSS) which implements the desktop What if? PSS developed by Klosterman (Environment and Planning B: Planning and Design 26:393–408, 1999; 2008). This paper describes the development of the online What if? suitability tool and the advantages and disadvantages of developing this novel solution. The paper focuses on a case study which used the tool for collaborative planning in the context of developing land suitability scenarios for the Metro North West sub-region in the Perth-Peel region undertaken by the Department of Planning in Western Australia. The paper concludes by discussing the lessons learned from formulating the land use suitability scenarios for Perth and outlines the next steps in the development and application of the online What if? tool.

Impacts of modified Richards equation on RegCM4 regional climate modeling over East Asia

AbstractTo remove the deficiency of the numerical solution of the mass conservation‐based Richards equation for soil moisture in a regional climate model (RegCM4 with its land surface component Community Land Model 3.5 (CLM3.5)), a revised numerical algorithm that is used in CLM4.5 is implemented into CLM3.5. Compared with in situ measurements, the modified numerical method improves the ground water table depth simulations in RegCM4. It also improves the temporal and spatial variability of soil moisture to some extent. Its impact on simulated summer precipitation is mixed, with improvements over three subregions in China but with increased errors in three other subregions. The impact on the simulated summer temperature is relatively small (with the mean biases changed by less than 10% over most subregions). The evapotranspiration differences between modified and control land‐atmosphere coupled simulations are enhanced over the northwest subregion and Tibetan Plateau compared to offline simulations due to land surface feedbacks to the atmosphere (in coupled simulations). Similarly the soil moisture differences in coupled simulations are geographically different from those in offline simulations over the eastern monsoon area. The summer precipitation differences between modified and control coupled simulations are found to be explained by the differences of both surface evapotranspiration and large‐scale water vapor flux convergence which have opposite signs over the northwest subregion and Tibetan Plateau but have the same signs over other subregions.

Soil productivity in the Yunnan province: Spatial distribution and sustainable utilization

Mountainous regions are more susceptible to food insecurity because of the shortage of farmland and the conflict between population and cultivated land resources. Here, we focused on the Yunnan province, a typical mountainous region in southwest China, where soil productivity plays a key role in agricultural development. The objectives were to assess spatial variation and sustainable utilization of soil productivity in the Yunnan province. We constructed a soil database based on 706 soil profiles collected from China’s second national soil survey, and assessed soil productivity with a soil productivity index model. We found significant differences in the soil productivity indexes among soil types; the indexes ranged from 0.12 to 0.85 and averaged 0.47. Higher productivity soils generally occurred in forest areas within the west and northwest sub-regions of Yunnan, while lower productivity soils tend to be located at low or extremely high elevations. The soil productivity index was lowest for barren land, followed by dry farmland, grassland, paddy fields, horticultural land, and forest lands. We found the productivity index to increase significantly as latitude increased and to vary with altitude at lower elevations. The soil productivity index ranged from 0.32 to 0.61 generally from the southeast sub-region to the northwest sub-region. Conversion of forest land or grassland to dry farmland may seriously degrade soil productivity. Local governments should consider soil productivity conservation practices when seeking to exploit land resources in mountainous areas. Yunnan's western sub-region has high potential for agricultural development. Effective soil remediation measures and soil and water conservation are needed in the central and southeast sub-regions to maintain sustainable soil productivity.

Simulated impacts of two types of ENSO events on tropical cyclone activity in the western North Pacific: large-scale atmospheric response

The present paper uses an atmospheric general circulation model to explore large-scale atmospheric response to various El Nino-Southern Oscillation events associated with tropical cyclone (TC) activity in the western North Pacific. The simulated response is basically consistent with and confirms the observed results. For eastern Pacific warm (EPW) event, anomalously wet ascent occurs over the tropical central/eastern Pacific and dry descent is over the western Pacific. This Walker circulation is associated with anomalous low-level convergence, reduced vertical wind shear (VWS), and enhanced genesis potential index (GPI) in the southeast sub-region. These are consistent with the observed increase of the TC formation in the southeast sub-region but decrease in the northwest sub-region during July–September (JAS) and the increase in the southwest and northwest sub-regions during October–December (OND). In addition, the strong westerly anomalies of the TC steering flow prevail in the East Asian coast, suppressing the TC northwestward or westward tracks. For eastern Pacific cold (EPC) event, all of the simulated variables show almost a mirror image of EPW. For central Pacific warm event, the anomalous Walker circulation shifts westward because of the westward shift of the maximum SST anomaly forcing. The anomalous subsidence associated with the western branch of the Walker circulation during OND shifts northward to the South China Seas, resulting in a decrease of the TC genesis there. The TC steering flow patterns during JAS are favorable for TCs to make landfall over Japan and Korea. Compared with EPC, the descending motion in the central/eastern Pacific is much stronger for central Pacific cold (CPC) event, accompanied by more enhanced VWS and reduced GPI in the southeast sub-region. Therefore, CPC provides a more adverse environment to the TC formation there during JAS and OND, consistent with the observed decrease of TC formation there. Moreover, the easterly anomalies of the TC steering flow dominate the tropics during JAS, enhancing TC activity in the east coast of China. Additionally, the convection over the western Pacific moves to the South China Sea during OND, favoring the TC genesis there.

AFGL 5157 NH3: a new stellar cluster in the forming process

We present the analysis of Spitzer/IRAC and near infrared imaging observation of AFGL 5157, an active star forming region. In the IRAC images, this region shows strong emissions of polycyclic aromatic hydrocarbons in channel 4 and emissions of H2 in channel 2. Many of the H2 features are aligned to form jet-like structures. Three bipolar jets in the NH3 core region and a couple of jets northwest of the core have been identified. We identify the possible driving agents of the bipolar jets and show them to be very young. An embedded cluster has been detected in the NH3 core; many members in the cluster have spectral energy distributions that increase from JHK bands toward longer wavelengths, indicative of their early evolutionary stages. Millimeter and submillimeter continuum emissions in the NH3 core and the northwest subregion are found to coincide spatially with these presumable Class 0/I sources. The existence of H2 bipolar jets and very young stellar objects suggests that star formation is continuing at the present epoch in these subregions. Combining information from previous studies, we propose a sequential star formation scenario in the whole AFGL 5157 region.

A cost analysis of the lumber and plywood industries in two Pacific Northwest sub-regions

Translog cost models are used to represent production technologies for the Pacific Northwest lumber and plywood industries. Expressions for cost elasticities are obtained along with measures for derived demand, factor substitution, and biased technological change. Emphasis is placed on the behavior of costs over output, the derived demand and substitutability of inputs due to changes in factor prices and technology, and the resulting effects on product prices. Estimation results over the 1950–79 sample period suggest the presence of output economies in specific industries, a potential impact of reduced factor prices, and the lack of a consistent trend in technological change across products and regional industries.