The Experts below are selected from a list of 23148 Experts worldwide ranked by ideXlab platform
Macdonald Richard - One of the best experts on this subject based on the ideXlab platform.
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 1
theRepository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:Revised data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment declined 6.5 percent over the twelve months ending January 2021. Area employment was 7,097 lower than one year earlier as the local recession continues into its second year. The pandemic has adversely affected nearly all local sectors—only the local construction center has experienced job growth over the past year. Ninety percent of the impact was felt in approximately one-half of area employment. For example, employment in the local leisure & hospitality sector was one-third lower over the past twelve months and the manufacturing sector shed 10 percent of its jobs over the same period. The St. Cloud Index of Leading Economic Indicators rose 0.8% in the recent period as the local economy is expected to improve from the weak numbers that have been seen since the onset of recession. Current business activity at surveyed firms was also improved as economic performance continued to rebound from historic weakness three months ago. 55 percent of surveyed firms report an increase in business activity over the past three months and only 15 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, business leaders express concern about the unfavorable impact that the new administration’s health care, regulatory, tax, trade, and immigration policies will have on their firm. Surveyed firms are less certain about the impact of the Biden administration’s infrastructure spending plans. In this quarter’s other special question, 42.4 percent of surveyed firms are strongly opposed to a potential ½-cent increase in the local sales tax in St. Cloud and Waite Park. Another 9.1 percent of firms are somewhat opposed to a sales tax hike, while 21.2 percent of firms are neutral. 15.2 percent of firms somewhat favor a local sales tax extension
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 3
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:St. Cloud area economic recovery has begun as year-over-year regional employment has grown and surveyed local firms project strong business activity. While the pandemic appears to have created scars in the local economy that plague some of our local service sectors, many area firms continue to report challenges that are typically associated with rapid expansion—labor shortages, price increases, accelerating wage growth, etc. Data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 4.3 percent over the twelve months ending July 2021. However, employment in the Stearns-Benton Metropolitan Statistical Area (MSA) is still 4,655 (4.4 percent) below its level two years ago. Recent job growth has been generally positive across most local sectors, but the leisure/hospitality and financial activities sectors saw a reduction in workers employed over the past twelve months. While financial activities employment has declined statewide, St. Cloud is the only region to see a current decline in leisure/hospitality sector employment. Employment in this sector is now 18.4 percent below its level in July 2019, compared to a decline of 10.4 percent statewide. The St. Cloud Index of Leading Economic Indicators rose 2.1% in the recent period and 10.3% in the last year as the local economy continues to rebound from the trough of the recession that ended in April 2020. Current business activity at surveyed firms continued to be strong compared to what is normally seen at this time of year. 60 percent of surveyed firms report an increase in business activity over the past three months and only 17 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, 43 percent of surveyed firms are either “greatly concerned” or “is our greatest concern” that the decline in labor force participation that has occurred since the onset of COVID is permanent. Also, one-third of surveyed businesses indicate the possibility that the recent increase in economywide inflation rates is not temporary is either a great concern or their greatest concern. In a final special question, only 12 percent of surveyed firms consider it to be likely or extremely likely that their firm will use cryptocurrencies for transactions within the next five years
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 2
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:The St. Cloud area economy is poised to exit recession as a variety of indicators suggest a broad-based recovery is on the horizon. While year-over-year data comparisons are now complicated by the historic decline in economic activity that occurred twelve months ago, there are signs that the pace of local economic activity continues to improve for many area firms. The pandemic has created scars in the local economy that will likely persist for months and years to come, but many area firms now seem to be experiencing challenges that are typically associated with rapid expansion—labor shortages, price increases, accelerating wage growth, etc. Employment data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 7.8 percent over the twelve months ending April 2021 but is still 4.4 percent below its pre-pandemic level of February 2020. Much of the recent job growth has come in three sectors that were most impacted by COVID-19 social distancing requirements: leisure & hospitality; other services; and retail trade. Current employment in these three sectors is still 3,128 lower than it was in April 2019. There is considerable upside potential for job gains in these three areas. The St. Cloud Index of Leading Economic Indicators rose 2.0% in the recent period as the local economy is expected to improve from the weak numbers that have been seen since the onset of recession. Current business activity at surveyed firms surged compared to three months ago. 62 percent of surveyed firms report an increase in business activity over the past three months and only 14 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, three-fourths of surveyed firms have not offered any incentives for their employees to receive a COVID-19 vaccine and 62 percent of firms have not attempted to verify which of their employees have received the vaccine. Many surveyed firms also indicate it has become more difficult to find workers because of increased unemployment compensation. For example, 60 percent of survey respondents indicate their applicant pool is smaller than it was last fall (at a time that more generous unemployment compensation benefits were phased out). Firms also report considerable supply chain issues. A majority of surveyed firms expect supply chain issues to continue or worsen in the coming months. Finally, in written responses, area firms explain how their business practices have been permanently altered by COVID-19
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 4
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:The economic recovery from the unrelenting COVID shock continues in the St. Cloud area as firms report an optimistic future outlook and employment grows. However, underlying this optimism are increases in wages, prices, capital expenditures, and worker shortages that may prove unsustainable in a post-COVID economy. Strong future optimism by surveyed firms is restrained by the reality that monetary and fiscal stimulus is abating perhaps faster than the pandemic. Data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 2% over the twelve months ending October 2021, but still 4,493 (4%) below its level two years ago. Recent job growth has been generally positive across most local sectors, but the education/health and financial activities sectors saw a reduction in workers employed over the past twelve months. In addition, while employment in the leisure/hospitality sector has increased over the past year, it is still 18.9% below its level in October 2019, almost twice the statewide decline in that industry. The St. Cloud Index of Leading Economic Indicators fell 2.4% from its record high three months ago but is still 1.3% higher in the last year as the local economy continues to rebound from the trough of the recession that ended in April 2020. Business activity at surveyed firms was solid over the past quarter. 62% of surveyed firms report an increase in business activity over the past three months and only 18% of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is very strong as 71% of survey respondents expect improved business conditions over the next six months and only 7% of firms anticipate decreased activity. In our first special question, 80% of surveyed firms report employee engagement is a “high priority” or “essential”. In a second special question, 44% of firms indicate they have on employees who are currently working regularly from home. 29% of firms have up to one-fourth of their workforce working from home and another 11% of firms report 26-50% of their employees are regularly telecommuting. For those firms with employees who work from home, the greatest share of workers are home 5 days per week. A similar percentage of workers are home three days per week. Finally, 18% of those firms that have employees working from home expect this to be a permanent arrangement. Another 13% of firms expect telecommuting will end within the next 12 months. We note that virtually all survey responses were collected prior to the recent news of the Omicron variant of COVID-19
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St. Cloud Area Quarterly Business Report, Vol. 22, No. 4
theRepository at St. Cloud State, 2020Co-Authors: Banaian King, Macdonald RichardAbstract:The St. Cloud area economy remains in recession as the uneven effects of the COVID-19 pandemic continue to plague the local labor market. While some local sectors are experiencing uninterrupted strong growth, the virus’ impact on the leisure/hospitality and other services sectors is creating historic existential challenges for some area firms. Overall local employment was 3.4 percent lower in October 2020 than it was one year earlier, but this is a clear improvement from what was seen in the June St. Cloud Area Quarterly Business Report (at which time an 11.5 percent year-over-year decline in area employment was reported). The St. Cloud Index of Leading Economic Indicators rose marginally over the past quarter, but was 3.5% higher over the last year. Current business activity at surveyed firms was weaker than usual as was their future outlook, although, on balance, area firms still expect improved business conditions over the next six months. In special questions, business leaders identify COVID-19 relief as the most important issue for the upcoming legislative session in St. Paul. Tax burden, job creation, and health care reform also rank high on firms’ list of legislative concerns. In a separate question, most firms report dedicating less than 5 percent of their spending on capital improvements meant to combat COVID-19
Banaian King - One of the best experts on this subject based on the ideXlab platform.
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 1
theRepository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:Revised data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment declined 6.5 percent over the twelve months ending January 2021. Area employment was 7,097 lower than one year earlier as the local recession continues into its second year. The pandemic has adversely affected nearly all local sectors—only the local construction center has experienced job growth over the past year. Ninety percent of the impact was felt in approximately one-half of area employment. For example, employment in the local leisure & hospitality sector was one-third lower over the past twelve months and the manufacturing sector shed 10 percent of its jobs over the same period. The St. Cloud Index of Leading Economic Indicators rose 0.8% in the recent period as the local economy is expected to improve from the weak numbers that have been seen since the onset of recession. Current business activity at surveyed firms was also improved as economic performance continued to rebound from historic weakness three months ago. 55 percent of surveyed firms report an increase in business activity over the past three months and only 15 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, business leaders express concern about the unfavorable impact that the new administration’s health care, regulatory, tax, trade, and immigration policies will have on their firm. Surveyed firms are less certain about the impact of the Biden administration’s infrastructure spending plans. In this quarter’s other special question, 42.4 percent of surveyed firms are strongly opposed to a potential ½-cent increase in the local sales tax in St. Cloud and Waite Park. Another 9.1 percent of firms are somewhat opposed to a sales tax hike, while 21.2 percent of firms are neutral. 15.2 percent of firms somewhat favor a local sales tax extension
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 3
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:St. Cloud area economic recovery has begun as year-over-year regional employment has grown and surveyed local firms project strong business activity. While the pandemic appears to have created scars in the local economy that plague some of our local service sectors, many area firms continue to report challenges that are typically associated with rapid expansion—labor shortages, price increases, accelerating wage growth, etc. Data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 4.3 percent over the twelve months ending July 2021. However, employment in the Stearns-Benton Metropolitan Statistical Area (MSA) is still 4,655 (4.4 percent) below its level two years ago. Recent job growth has been generally positive across most local sectors, but the leisure/hospitality and financial activities sectors saw a reduction in workers employed over the past twelve months. While financial activities employment has declined statewide, St. Cloud is the only region to see a current decline in leisure/hospitality sector employment. Employment in this sector is now 18.4 percent below its level in July 2019, compared to a decline of 10.4 percent statewide. The St. Cloud Index of Leading Economic Indicators rose 2.1% in the recent period and 10.3% in the last year as the local economy continues to rebound from the trough of the recession that ended in April 2020. Current business activity at surveyed firms continued to be strong compared to what is normally seen at this time of year. 60 percent of surveyed firms report an increase in business activity over the past three months and only 17 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, 43 percent of surveyed firms are either “greatly concerned” or “is our greatest concern” that the decline in labor force participation that has occurred since the onset of COVID is permanent. Also, one-third of surveyed businesses indicate the possibility that the recent increase in economywide inflation rates is not temporary is either a great concern or their greatest concern. In a final special question, only 12 percent of surveyed firms consider it to be likely or extremely likely that their firm will use cryptocurrencies for transactions within the next five years
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 2
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:The St. Cloud area economy is poised to exit recession as a variety of indicators suggest a broad-based recovery is on the horizon. While year-over-year data comparisons are now complicated by the historic decline in economic activity that occurred twelve months ago, there are signs that the pace of local economic activity continues to improve for many area firms. The pandemic has created scars in the local economy that will likely persist for months and years to come, but many area firms now seem to be experiencing challenges that are typically associated with rapid expansion—labor shortages, price increases, accelerating wage growth, etc. Employment data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 7.8 percent over the twelve months ending April 2021 but is still 4.4 percent below its pre-pandemic level of February 2020. Much of the recent job growth has come in three sectors that were most impacted by COVID-19 social distancing requirements: leisure & hospitality; other services; and retail trade. Current employment in these three sectors is still 3,128 lower than it was in April 2019. There is considerable upside potential for job gains in these three areas. The St. Cloud Index of Leading Economic Indicators rose 2.0% in the recent period as the local economy is expected to improve from the weak numbers that have been seen since the onset of recession. Current business activity at surveyed firms surged compared to three months ago. 62 percent of surveyed firms report an increase in business activity over the past three months and only 14 percent of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is also improved as local companies expect better business conditions over the next six months. In special questions, three-fourths of surveyed firms have not offered any incentives for their employees to receive a COVID-19 vaccine and 62 percent of firms have not attempted to verify which of their employees have received the vaccine. Many surveyed firms also indicate it has become more difficult to find workers because of increased unemployment compensation. For example, 60 percent of survey respondents indicate their applicant pool is smaller than it was last fall (at a time that more generous unemployment compensation benefits were phased out). Firms also report considerable supply chain issues. A majority of surveyed firms expect supply chain issues to continue or worsen in the coming months. Finally, in written responses, area firms explain how their business practices have been permanently altered by COVID-19
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St. Cloud Area Quarterly Business Report, Vol. 23, No. 4
The Repository at St. Cloud State, 2021Co-Authors: Banaian King, Macdonald RichardAbstract:The economic recovery from the unrelenting COVID shock continues in the St. Cloud area as firms report an optimistic future outlook and employment grows. However, underlying this optimism are increases in wages, prices, capital expenditures, and worker shortages that may prove unsustainable in a post-COVID economy. Strong future optimism by surveyed firms is restrained by the reality that monetary and fiscal stimulus is abating perhaps faster than the pandemic. Data released by the Minnesota Department of Employment and Economic Development (DEED) indicate St. Cloud area employment increased 2% over the twelve months ending October 2021, but still 4,493 (4%) below its level two years ago. Recent job growth has been generally positive across most local sectors, but the education/health and financial activities sectors saw a reduction in workers employed over the past twelve months. In addition, while employment in the leisure/hospitality sector has increased over the past year, it is still 18.9% below its level in October 2019, almost twice the statewide decline in that industry. The St. Cloud Index of Leading Economic Indicators fell 2.4% from its record high three months ago but is still 1.3% higher in the last year as the local economy continues to rebound from the trough of the recession that ended in April 2020. Business activity at surveyed firms was solid over the past quarter. 62% of surveyed firms report an increase in business activity over the past three months and only 18% of firms experienced a decrease in activity over the past quarter. The future outlook of surveyed firms is very strong as 71% of survey respondents expect improved business conditions over the next six months and only 7% of firms anticipate decreased activity. In our first special question, 80% of surveyed firms report employee engagement is a “high priority” or “essential”. In a second special question, 44% of firms indicate they have on employees who are currently working regularly from home. 29% of firms have up to one-fourth of their workforce working from home and another 11% of firms report 26-50% of their employees are regularly telecommuting. For those firms with employees who work from home, the greatest share of workers are home 5 days per week. A similar percentage of workers are home three days per week. Finally, 18% of those firms that have employees working from home expect this to be a permanent arrangement. Another 13% of firms expect telecommuting will end within the next 12 months. We note that virtually all survey responses were collected prior to the recent news of the Omicron variant of COVID-19
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St. Cloud Area Quarterly Business Report, Vol. 22, No. 4
theRepository at St. Cloud State, 2020Co-Authors: Banaian King, Macdonald RichardAbstract:The St. Cloud area economy remains in recession as the uneven effects of the COVID-19 pandemic continue to plague the local labor market. While some local sectors are experiencing uninterrupted strong growth, the virus’ impact on the leisure/hospitality and other services sectors is creating historic existential challenges for some area firms. Overall local employment was 3.4 percent lower in October 2020 than it was one year earlier, but this is a clear improvement from what was seen in the June St. Cloud Area Quarterly Business Report (at which time an 11.5 percent year-over-year decline in area employment was reported). The St. Cloud Index of Leading Economic Indicators rose marginally over the past quarter, but was 3.5% higher over the last year. Current business activity at surveyed firms was weaker than usual as was their future outlook, although, on balance, area firms still expect improved business conditions over the next six months. In special questions, business leaders identify COVID-19 relief as the most important issue for the upcoming legislative session in St. Paul. Tax burden, job creation, and health care reform also rank high on firms’ list of legislative concerns. In a separate question, most firms report dedicating less than 5 percent of their spending on capital improvements meant to combat COVID-19
Yiping Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of Cloudiness change on net ecosystem exchange light use efficiency and water use efficiency in typical ecosystems of china
Agricultural and Forest Meteorology, 2011Co-Authors: Mi Zhang, Guirui Yu, Jie Zhuang, Randy Gentry, Yuling Fu, Leiming Zhang, Qiufeng Wang, Yiping Zhang, Yanfen Wang, Yingnian LiAbstract:As a weather element, Clouds can affect CO(2) exchange between terrestrial ecosystems and the atmosphere by altering environmental conditions, such as solar radiation received on the ground surface, temperature, and moisture. Based on the flux data measured at five typical ecosystems of China during mid-growing season (June-August) from 2003 to 2006, we analyzed the responses of net ecosystem exchange of carbon dioxide (NEE), light use efficiency (LUE, defined as Gross ecosystem photosynthesis (GEP)/Photosynthetically active radiation (PAR)), and water use efficiency (WUE, defined as GEP/Evapotranspiration (ET)) to the changes in Cloudiness. The five ecological sites included Changbaishan temperate mixed forest (CBS), Dinghushan subtropical evergreen broad-leaved forest (DHS), Xishuangbanna tropical rainforest (XSBN), Inner Mongolia semi-arid Leymus chinensis steppe (NMG), and Haibei alpine frigid Potentilla fruticosa shrub (HB). Our analyses show that Cloudy sky conditions with Cloud Index (k(t)) values between 0.4 and 0.6 increased NEE, LUE, and WUE of the ecosystems at CBS, DHS, NMG and HB from June to August. The LUE of tropical rainforest at XSBN was higher under Cloudy than under clear sky conditions, but NEE and WUE did not decrease significantly under clear sky conditions from June to August. The increase in GEP with increasing diffuse radiation received by ecosystems under Cloudy skies was the main reason that caused the increases in LUE and net carbon uptake in forest ecosystem at CBS, DHS, and alpine shrub ecosystem at HB, compared with clear skies. Moreover, for the ecosystem at CBS, DHS, and HB, when sky condition became from clear to Cloudy, GEP increased and ET decreased with decreasing VPD, leading to the increase in WUE and NEE under Cloudy sky conditions. The decrease in Re with decreasing temperature and increase in GEP with decreasing VPD under Cloudy skies led to the increase in LUE. WUE, and net carbon uptake of semi-arid steppe at NMG, compared to clear skies. These different responses among the five ecosystems are attributable to the differences in canopy characteristics and water conditions. From June to August, the peaks of the k(t) frequency distribution in temperate ecosystems (e.g., CBS, NMG, and HB) were larger than 0.5, but they were smaller than 0.4 in subtropical/tropical forest ecosystems (e.g., DHS and XSBN). These results suggest that the pattern of Cloudiness during the years from 2003 to 2006 in the five ecosystems was not the best condition for their net carbon uptake. This study highlights the importance of Cloudiness factor in the prediction of net carbon absorption in the Asia monsoon region under climate change. (C) 2011 Elsevier B.V. All rights reserved.
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effects of Cloudiness change on net ecosystem exchange light use efficiency and water use efficiency in typical ecosystems of china
Agricultural and Forest Meteorology, 2011Co-Authors: Mi Zhang, Jie Zhuang, Randy Gentry, Leiming Zhang, Qiufeng Wang, Xiaomin Sun, Xuefa Wen, Shijie Han, Junhua Yan, Yiping ZhangAbstract:As a weather element, Clouds can affect CO(2) exchange between terrestrial ecosystems and the atmosphere by altering environmental conditions, such as solar radiation received on the ground surface, temperature, and moisture. Based on the flux data measured at five typical ecosystems of China during mid-growing season (June-August) from 2003 to 2006, we analyzed the responses of net ecosystem exchange of carbon dioxide (NEE), light use efficiency (LUE, defined as Gross ecosystem photosynthesis (GEP)/Photosynthetically active radiation (PAR)), and water use efficiency (WUE, defined as GEP/Evapotranspiration (ET)) to the changes in Cloudiness. The five ecological sites included Changbaishan temperate mixed forest (CBS), Dinghushan subtropical evergreen broad-leaved forest (DHS), Xishuangbanna tropical rainforest (XSBN), Inner Mongolia semi-arid Leymus chinensis steppe (NMG), and Haibei alpine frigid Potentilla fruticosa shrub (HB). Our analyses show that Cloudy sky conditions with Cloud Index (k(t)) values between 0.4 and 0.6 increased NEE, LUE, and WUE of the ecosystems at CBS, DHS, NMG and HB from June to August. The LUE of tropical rainforest at XSBN was higher under Cloudy than under clear sky conditions, but NEE and WUE did not decrease significantly under clear sky conditions from June to August. The increase in GEP with increasing diffuse radiation received by ecosystems under Cloudy skies was the main reason that caused the increases in LUE and net carbon uptake in forest ecosystem at CBS, DHS, and alpine shrub ecosystem at HB, compared with clear skies. Moreover, for the ecosystem at CBS, DHS, and HB, when sky condition became from clear to Cloudy, GEP increased and ET decreased with decreasing VPD, leading to the increase in WUE and NEE under Cloudy sky conditions. The decrease in Re with decreasing temperature and increase in GEP with decreasing VPD under Cloudy skies led to the increase in LUE. WUE, and net carbon uptake of semi-arid steppe at NMG, compared to clear skies. These different responses among the five ecosystems are attributable to the differences in canopy characteristics and water conditions. From June to August, the peaks of the k(t) frequency distribution in temperate ecosystems (e.g., CBS, NMG, and HB) were larger than 0.5, but they were smaller than 0.4 in subtropical/tropical forest ecosystems (e.g., DHS and XSBN). These results suggest that the pattern of Cloudiness during the years from 2003 to 2006 in the five ecosystems was not the best condition for their net carbon uptake. This study highlights the importance of Cloudiness factor in the prediction of net carbon absorption in the Asia monsoon region under climate change. (C) 2011 Elsevier B.V. All rights reserved.
Mi Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of Cloudiness change on net ecosystem exchange light use efficiency and water use efficiency in typical ecosystems of china
Agricultural and Forest Meteorology, 2011Co-Authors: Mi Zhang, Guirui Yu, Jie Zhuang, Randy Gentry, Yuling Fu, Leiming Zhang, Qiufeng Wang, Yiping Zhang, Yanfen Wang, Yingnian LiAbstract:As a weather element, Clouds can affect CO(2) exchange between terrestrial ecosystems and the atmosphere by altering environmental conditions, such as solar radiation received on the ground surface, temperature, and moisture. Based on the flux data measured at five typical ecosystems of China during mid-growing season (June-August) from 2003 to 2006, we analyzed the responses of net ecosystem exchange of carbon dioxide (NEE), light use efficiency (LUE, defined as Gross ecosystem photosynthesis (GEP)/Photosynthetically active radiation (PAR)), and water use efficiency (WUE, defined as GEP/Evapotranspiration (ET)) to the changes in Cloudiness. The five ecological sites included Changbaishan temperate mixed forest (CBS), Dinghushan subtropical evergreen broad-leaved forest (DHS), Xishuangbanna tropical rainforest (XSBN), Inner Mongolia semi-arid Leymus chinensis steppe (NMG), and Haibei alpine frigid Potentilla fruticosa shrub (HB). Our analyses show that Cloudy sky conditions with Cloud Index (k(t)) values between 0.4 and 0.6 increased NEE, LUE, and WUE of the ecosystems at CBS, DHS, NMG and HB from June to August. The LUE of tropical rainforest at XSBN was higher under Cloudy than under clear sky conditions, but NEE and WUE did not decrease significantly under clear sky conditions from June to August. The increase in GEP with increasing diffuse radiation received by ecosystems under Cloudy skies was the main reason that caused the increases in LUE and net carbon uptake in forest ecosystem at CBS, DHS, and alpine shrub ecosystem at HB, compared with clear skies. Moreover, for the ecosystem at CBS, DHS, and HB, when sky condition became from clear to Cloudy, GEP increased and ET decreased with decreasing VPD, leading to the increase in WUE and NEE under Cloudy sky conditions. The decrease in Re with decreasing temperature and increase in GEP with decreasing VPD under Cloudy skies led to the increase in LUE. WUE, and net carbon uptake of semi-arid steppe at NMG, compared to clear skies. These different responses among the five ecosystems are attributable to the differences in canopy characteristics and water conditions. From June to August, the peaks of the k(t) frequency distribution in temperate ecosystems (e.g., CBS, NMG, and HB) were larger than 0.5, but they were smaller than 0.4 in subtropical/tropical forest ecosystems (e.g., DHS and XSBN). These results suggest that the pattern of Cloudiness during the years from 2003 to 2006 in the five ecosystems was not the best condition for their net carbon uptake. This study highlights the importance of Cloudiness factor in the prediction of net carbon absorption in the Asia monsoon region under climate change. (C) 2011 Elsevier B.V. All rights reserved.
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effects of Cloudiness change on net ecosystem exchange light use efficiency and water use efficiency in typical ecosystems of china
Agricultural and Forest Meteorology, 2011Co-Authors: Mi Zhang, Jie Zhuang, Randy Gentry, Leiming Zhang, Qiufeng Wang, Xiaomin Sun, Xuefa Wen, Shijie Han, Junhua Yan, Yiping ZhangAbstract:As a weather element, Clouds can affect CO(2) exchange between terrestrial ecosystems and the atmosphere by altering environmental conditions, such as solar radiation received on the ground surface, temperature, and moisture. Based on the flux data measured at five typical ecosystems of China during mid-growing season (June-August) from 2003 to 2006, we analyzed the responses of net ecosystem exchange of carbon dioxide (NEE), light use efficiency (LUE, defined as Gross ecosystem photosynthesis (GEP)/Photosynthetically active radiation (PAR)), and water use efficiency (WUE, defined as GEP/Evapotranspiration (ET)) to the changes in Cloudiness. The five ecological sites included Changbaishan temperate mixed forest (CBS), Dinghushan subtropical evergreen broad-leaved forest (DHS), Xishuangbanna tropical rainforest (XSBN), Inner Mongolia semi-arid Leymus chinensis steppe (NMG), and Haibei alpine frigid Potentilla fruticosa shrub (HB). Our analyses show that Cloudy sky conditions with Cloud Index (k(t)) values between 0.4 and 0.6 increased NEE, LUE, and WUE of the ecosystems at CBS, DHS, NMG and HB from June to August. The LUE of tropical rainforest at XSBN was higher under Cloudy than under clear sky conditions, but NEE and WUE did not decrease significantly under clear sky conditions from June to August. The increase in GEP with increasing diffuse radiation received by ecosystems under Cloudy skies was the main reason that caused the increases in LUE and net carbon uptake in forest ecosystem at CBS, DHS, and alpine shrub ecosystem at HB, compared with clear skies. Moreover, for the ecosystem at CBS, DHS, and HB, when sky condition became from clear to Cloudy, GEP increased and ET decreased with decreasing VPD, leading to the increase in WUE and NEE under Cloudy sky conditions. The decrease in Re with decreasing temperature and increase in GEP with decreasing VPD under Cloudy skies led to the increase in LUE. WUE, and net carbon uptake of semi-arid steppe at NMG, compared to clear skies. These different responses among the five ecosystems are attributable to the differences in canopy characteristics and water conditions. From June to August, the peaks of the k(t) frequency distribution in temperate ecosystems (e.g., CBS, NMG, and HB) were larger than 0.5, but they were smaller than 0.4 in subtropical/tropical forest ecosystems (e.g., DHS and XSBN). These results suggest that the pattern of Cloudiness during the years from 2003 to 2006 in the five ecosystems was not the best condition for their net carbon uptake. This study highlights the importance of Cloudiness factor in the prediction of net carbon absorption in the Asia monsoon region under climate change. (C) 2011 Elsevier B.V. All rights reserved.
Richard Perez - One of the best experts on this subject based on the ideXlab platform.
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producing satellite derived irradiances in complex arid terrain
Solar Energy, 2004Co-Authors: Richard Perez, Pierre Ineichen, Marek Kmiecik, Kathleen Moore, David Renne, R GeorgeAbstract:This paper describes a methodology to correct satellite-derived irradiances over complex terrain for models that use the visible satellite channel as main input for Cloud Index determination. Complex terrain is characterized by high reflectance surface and or the juxtaposition of high and low reflectance surfaces (e.g., desert plains and forested ridges). The correction consists of (1) climate dependent post-model clear sky calibration and (2) singularity identification and removal.
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a new operational model for satellite derived irradiances description and validation
Solar Energy, 2002Co-Authors: Richard Perez, Pierre Ineichen, Kathy Moore, Marek Kmiecik, Cyril Chain, R George, Frank VignolaAbstract:We present a new simple model capable of exploiting geostationary satellite visible images for the production of site/time-specific global and direct irradiances The new model features new clear sky global and direct irradiance functions, a new Cloud-Index-to-irradiance Index function, and a new global-to-direct-irradiance conversion model. The model can also exploit operationally available snow cover resource data, while deriving local ground specular reflectance characteristics from the stream of incoming satellite data. Validation against 10 US locations representing a wide range of climatic environments indicates that model performance is systematically improved, compared to current visible-channel-based modeling practice.
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derivation of Cloud Index from geostationary satellites and application to the production of solar irradiance and daylight illuminance data
Theoretical and Applied Climatology, 1999Co-Authors: Pierre Ineichen, Richard PerezAbstract:We investigate in the present paper the relationship between satellite count, global irradiance and other solar and illumination resource components, bringing a particular attention to low solar elevation situations (below 20°) which are very important in northern latitudes. Our investigation is based on data from two geostationary satellites, METEO-SAT and GOES, backed by ground measurements in Switzerland and the northeastern USA. The study of different clear sky normalizations lead to the conclusion that a linear correlation between the global clearness Index and the irradiance (like the heliosat method) would be inaccurate for low solar elevations, and therefore for high latitude regions. We developed a model that directly relates an elevation dependent clearness Index to the could Index. This methodology presents a definite advantage because it can be generalized to address the clearness Index of other solar radiation components, besides global irradiance, such as direct irradiance, diffuse illuminance, etc. The correlations described in this paper were developed on the data from Geneva (in the frame of the EC program Satellight) and evaluated on two other independent data sets (Albany, USA and Lausanne, Switzerland). Their precisions, on a hourly basis, are respectively 30%, 40% and 60% for the global, diffuse and beam components) (90, 55 and 95 W/m2). The use of independent data for the derivation and the validation of the models shows that those can be used in a wide range of locations, even if the applicability has to be assessed for very different climates.