USER INFORMATION SATISFACTION: TOWARD CONCEPTUAL CLARITY

User information satisfaction (UIS) has been generally recognized by management information systems (MIS) researchers as one of the more important indicators of success in designing and implementing MIS. However, the existence of various UIS measures using different definitions of UIS has resulted in the use of inconsistent theoretical constructs and an inability to interpret across studies. Using consumer satisfaction research as a reference theory, this paper develops a conceptual model of UIS to clarify the concept. In the model, UIS is considered a function of organizational factors and the discrepancy between expected information service quality and perceived information service quality. This discrepancy, in turn, is a result of a series of gaps which are related to the MIS development and information service delivery processes. The implications of this model for future research and practice are discussed

An Examination of Factors for the Strategic Use of Information Systems in the Healthcare Industry

The potential use of information systems technology (IST) as a competitive weapon has been of enormous interest to many academic scholars and practitioners. However, the importance of identifying factors that organizations must deal with in the process of achieving IST competitive advantages has received inadequate research attention. This article attempts to identify these important factors for the strategic use of IST by examining the multifaceted role of IST in the healthcare context. Three propositions are developed from (1) re-examining a variety of successful IST applications both within and outside healthcare organizations, (2) re-applying the integration concept from the literature, and (3) examining field experiences in the healthcare industry. These propositions should serve as a basis for future empirical investigations into IST strategic applications

The Role of African Easterly Wave on Dust Transport and the Interaction Between Saharan Dust Layer and Atlantic ITCZ During Boreal Summer

Saharan dust outbreaks not only transport large amount of dust to the northern Atlantic Ocean, but also alter African easterly jet and wave activities along the jet by changing north-south temperature gradient. Recent modeling and observational studies show that during periods of enhance outbreaks, rainfall on the northern part of ITCZ increases in conjunction with a northward shift of ITCZ toward the dust layer. In this paper, we study the radiative forcing of Saharan dust and its interactions with the Atlantic Inter-tropical Convergence Zone (ITCZ), through African easterly waves (AEW), African easterly jet (AEJ), using the Terra/Aqua observations as well as MERRA data. Using band pass filtered EOF analysis, we find that African easterly waves propagating westward along two principal tracks, centered at 15-25N and 5-10N respectively. The easterly waves in the northern track are slower, with propagation speed of 9 ms-1, and highly correlated with major dust outbreak over North Africa. On the other hand, easterly waves along the southern track are faster with propagating speed of 10 ms-1, and are closely tied to rainfall/cloud variations along the Atlantic ITCZ. Dust transport along the southern track leads rainfall/cloud anomalies in the same region by one or two days, suggesting the southern tracks of dust outbreak are regions of strong interaction between Saharan dust layer and Atlantic ITCZ. Possible linkage between two tracks of easterly waves, as well as the long-term change of easterly wave activities and dust outbreaks, are also discussed

The Aerosol-Monsoon Climate System of Asia

In Asian monsoon countries such as China and India, human health and safety problems caused by air-pollution are worsening due to the increased loading of atmospheric pollutants stemming from rising energy demand associated with the rapid pace of industrialization and modernization. Meanwhile, uneven distribution of monsoon rain associated with flash flood or prolonged drought, has caused major loss of human lives, and damages in crop and properties with devastating societal impacts on Asian countries. Historically, air-pollution and monsoon research are treated as separate problems. However a growing number of recent studies have suggested that the two problems may be intrinsically intertwined and need to be studied jointly. Because of complexity of the dynamics of the monsoon systems, aerosol impacts on monsoons and vice versa must be studied and understood in the context of aerosol forcing in relationship to changes in fundamental driving forces of the monsoon climate system (e.g. sea surface temperature, land-sea contrast etc.) on time scales from intraseasonal variability (~weeks) to climate change (~ multi-decades). Indeed, because of the large contributions of aerosols to the global and regional energy balance of the atmosphere and earth surface, and possible effects of the microphysics of clouds and precipitation, a better understanding of the response to climate change in Asian monsoon regions requires that aerosols be considered as an integral component of a fully coupled aerosol-monsoon system on all time scales. In this paper, using observations and results from climate modeling, we will discuss the coherent variability of the coupled aerosol-monsoon climate system in South Asia and East Asia, including aerosol distribution and types, with respect to rainfall, moisture, winds, land-sea thermal contrast, heat sources and sink distributions in the atmosphere in seasonal, interannual to climate change time scales. We will show examples of how elevated absorbing aerosols (dust and black carbon) may interact with monsoon dynamics to produce feedback effects on the atmospheric water cycle, leading to in accelerated melting of snowpacks over the Himalayas and Tibetan Plateau, and subsequent changes in evolution of the pre-monsoon and peak monsoon rainfall, moisture and wind distributions in South Asia and East Asia

A Robust Response of the Hadley Circulation to Global Warming

Tropical rainfall is expected to increase in a warmer climate. Yet, recent studies have inferred that the Hadley Circulation (HC), which is primarily driven by latent heating from tropical rainfall, is weakened under global warming. Here, we show evidence of a robust intensification of the HC from analyses of 33 CMIP5 model projections under a scenario of 1 per year CO2 emission increase. The intensification is manifested in a deep-tropics squeeze, characterized by a pronounced increase in the zonal mean ascending motion in the mid and upper troposphere, a deepening and narrowing of the convective zone and enhanced rainfall in the deep tropics. These changes occur in conjunction with a rise in the region of maximum outflow of the HC, with accelerated meridional mass outflow in the uppermost branch of the HC away from the equator, coupled to a weakened inflow in the return branches of the HC in the lower troposphere

Competing Influences of Greenhouse Warming and Aerosols on Asian Summer Monsoon Circulation and Rainfall

In this paper, we have compared and contrasted competing and amplifying influences on the global and regional drivers, circulation and rainfall responses of the Asian monsoon under global greenhouse warming (GHG) and aerosol forcing, based on CMIP5 historical simulations. Under GHG-only forcing, the land warms much faster than the ocean, magnifying the pre-industrial climatological land-ocean thermal contrast and hemispheric asymmetry, i.e., warmer northern than southern hemisphere. A steady increasing warm-ocean-warmer-land (WOWL) trend has been in effect since the 1950's substantially increasing moisture transport from adjacent oceans, and enhancing rainfall over the Asian monsoon regions. However, under GHG warming, increased atmospheric stability due to strong reduction in mid-tropospheric and near surface relative humidity coupled to an expanding subsidence areas, associated with the Deep Tropical Squeeze (DTS, Lau and Kim, 2015b) strongly suppress monsoon convection and rainfall over subtropical and extratropical land, leading to a weakening of the Asian monsoon meridional circulation. The inclusion of aerosol emissions strongly masks WOWL, by over 60% over the northern hemisphere, negating to a large extent the rainfall increase due to GHG warming, and leading to a further weakening of the monsoon circulation, through increasing atmospheric stability, most likely associated with aerosol solar dimming and semi-direct effects. Overall, we find that GHG exerts stronger positive rainfall sensitivity, but less negative circulation sensitivity in SASM compared to EASM. In contrast, aerosols exert stronger negative impacts on rainfall, but less negative impacts on circulation in EASM compared to SASM

Observational Evidence of EHP Effects on the Melting of Snowpack over the Tibetan Plateau

Observational evidences are presented showing that the Indo-Gangetic Plain (IGP) regions, bounded by the high altitude Himalayan mountains, are subject to heavy loading of absorbing aerosols, i.e., black carbon and dust, which can lead to widespread enhancement warming over the Tibetan Plateau and accelerated snowmelt in the western Tibetan Plateau (WTP) and Himalayas. The two pre-monsoon seasons of 2004 and 2005 were strikingly contrasting in terms of the aerosol loading over IGP. The warming of the TP in 2004 relative to 2005 was widespread, covering most of the WTP and Himalayas. This warming is closely linked to patterns of the snow melt. Consistent with the Elevated Heat Pump hypothesis, we find that increased loading of absorbing aerosols over IGP in the pre-monsoon season is associated with increased heating of the upper troposphere by dynamical feedback induced by aerosol heating, and enhances the rate of snowmelt over Himalayas and the WTP in April-May. Composite analysis with more contrasting years also shows that the heating of the troposphere by elevated dust and black carbon aerosols in the boreal spring can lead to widespread enhanced land-atmosphere warming, and accelerated snow melt in the Himalayas and Tibetan Plateau

Changes in the Intensity and Frequency of Atmospheric Blocking and Associated Heat Waves During Northern Summer Over Eurasia in the CMIP5 Model Simulations

The Russia heat wave and wild fires of the summer of 2010 was the most extreme weather event in the history of the country. Studies show that the root cause of the 2010 Russia heat wave/wild fires was an atmospheric blocking event which started to develop at the end of June and peaked around late July and early August. Atmospheric blocking in the summer of 2010 was anomalous in terms of the size, duration, and the location, which shifted to the east from the normal location. This and other similar continental scale severe summertime heat waves and blocking events in recent years have raised the question of whether such events are occurring more frequently and with higher intensity in a warmer climate induced by greenhouse gases. We studied the spatial and temporal distributions of the occurrence and intensity of atmospheric blocking and associated heat waves for northern summer over Eurasia based on CMIPS model simulations. To examine the global warming induced change of atmospheric blocking and heat waves, experiments for a high emissions scenario (RCP8.S) and a medium mitigation scenario (RCP4.S) are compared to the 20th century simulations (historical). Most models simulate the mean distributions of blockings reasonably well, including major blocking centers over Eurasia, northern Pacific, and northern Atlantic. However, the models tend to underestimate the number of blockings compared to MERRA and NCEPIDOE reanalysis, especially in western Siberia. Models also reproduced associated heat waves in terms of the shifting in the probability distribution function of near surface temperature. Seven out of eight models used in this study show that the frequency of atmospheric blocking over the Europe will likely decrease in a warmer climate, but slightly increase over the western Siberia. This spatial pattern resembles the blocking in the summer of 2010, indicating the possibility of more frequent occurrences of heat waves in western Siberia. In this talk, we will also discuss the potential effect of atmosphere-land feedback, particularly how the wetter spring affects the frequency and intensity of atmospheric blocking and heat wave during summer