A Multidecadal Variation in Summer Season Diurnal Rainfall in the Central United States*

Hu, Qi

doi:10.1175/1520-0442(2003)016<0174:amviss>2.0.co;2

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…Previous studies have shown that warm-season rainfall depends on the preceding soil moisture conditions, particularly over the GP (Koster et al 2004), which is in turn influenced by the interannual variation of SST forcing. We would therefore expect that the diurnal cycle of rainfall is impacted by soil moisture as well (e.g., Hu 2003). In fact, an inspection of the individual ensemble members shows that the amplitude of the simulated diurnal cycle of rainfall does indeed vary considerably among the ensemble members, though that is not the case for the phase of the diurnal cycle (our main focus).…”

Section: Experiments and Analysismentioning

confidence: 96%

An Analysis of the Warm-Season Diurnal Cycle over the Continental United States and Northern Mexico in General Circulation Models

Lee

Schubert

Suárez

et al. 2007

Journal of Hydrometeorology

100

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The diurnal cycle of warm-season rainfall over the continental United States and northern Mexico is analyzed in three global atmospheric general circulation models (AGCMs) from NCEP, GFDL, and the NASA Global Modeling Assimilation Office (GMAO). The results for each model are based on an ensemble of five summer simulations forced with climatological sea surface temperatures.Although the overall patterns of time-mean (summer) rainfall and low-level winds are reasonably well simulated, all three models exhibit substantial regional deficiencies that appear to be related to problems with the diurnal cycle. Especially prominent are the discrepancies in the diurnal cycle of precipitation over the eastern slopes of the Rocky Mountains and adjacent Great Plains, including the failure to adequately capture the observed nocturnal peak. Moreover, the observed late afternoon-early evening eastward propagation of convection from the mountains into the Great Plains is not adequately simulated, contributing to the deficiencies in the diurnal cycle in the Great Plains. In the southeast United States, the models show a general tendency to rain in the early afternoon-several hours earlier than observed. Over the North American monsoon region in the southwest United States and northern Mexico, the phase of the broadscale diurnal convection appears to be reasonably well simulated, though the coarse resolution of the runs precludes the simulation of key regional phenomena.All three models employ deep convection schemes that assume fundamentally the same buoyancy closure based on simplified versions of the Arakawa-Schubert scheme. Nevertheless, substantial differences between the models in the diurnal cycle of convection highlight the important differences in their implementations and interactions with the boundary layer scheme. An analysis of local diurnal variations of convective available potential energy (CAPE) shows an overall tendency for an afternoon peak-a feature well simulated by the models. The simulated diurnal cycle of rainfall is in phase with the local CAPE variation over the southeast United States and the Rocky Mountains where the local surface boundary forcing is important in regulating the diurnal cycle of convection. On the other hand, the simulated diurnal cycle of rainfall tends to be too strongly tied to CAPE over the Great Plains, where the observed precipitation and CAPE are out of phase, implying that free atmospheric large-scale forcing plays a more important role than surface heat fluxes in initiating or inhibiting convection. *

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Section: Experiments and Analysismentioning

confidence: 96%

An Analysis of the Warm-Season Diurnal Cycle over the Continental United States and Northern Mexico in General Circulation Models

Lee

Schubert

Suárez

et al. 2007

Journal of Hydrometeorology

100

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“…It is difficult to determine if the future change in onshore flow can be explained by changes in climate. Hu [2003] shows large interannual variations in the moisture flux to the central United States between 1950 and 2000.…”

Section: Changes In Factors Affecting Us Air Quality: 1990–2090mentioning

confidence: 99%

How does climate change contribute to surface ozone change over the United States?

Murazaki¹,

2006

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[1] The impact of climate change on U.S. surface ozone levels is investigated. We simulated two 10 year periods using the global chemical transport model MOZART-2 (Model of Ozone and Related chemical Tracers version 2): 1990-2000 and 2090-2100. In each case, MOZART-2 is driven by meteorology from the National Center for Atmospheric Research (NCAR) coupled Climate Systems Model (CSM) 1.0 forced with the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1 scenario. During both periods the chemical emissions are fixed at 1990s levels, so that only changes in climate are allowed to impact ozone. The simulated surface ozone concentration during the 1990s is compared with observations from the Environmental Protection Agency's Aerometric Information Retrieval System (EPA AIRS) monitoring sites. Model-measurement correlations are high, but MOZART-2 overpredicts ozone especially over the eastern United States. The impact of climate change is calculated separately for background ozone and for the ozone generated through U.S. NO x emissions. Our results show that the response of ozone to climate change in polluted regions is not the same as in remote regions. MOZART-2 predicts a 0-2 ppbv decrease in background ozone in the future simulation over the United States but an increase in ozone produced internally within the United States of up to 6 ppbv. The decrease in background ozone is attributed to a future decrease in the lifetime of ozone in regions of low NO x . Over the western United States the decrease in background ozone approximately cancels the increase in locally produced ozone. As a result, the main impact of future climate change on ozone is centered over the eastern United States, where future ozone increases up to 5 ppbv. We predict that in the future over the northeast United States, up to 12 additional days each year will exceed the maximum daily 8-hour averaged ozone limit of 80 ppbv. Various climatic factors are identified which impact the net future increase in ozone over the United States including changes in temperature, water vapor, clouds, transport, and lightning NO x . Significant future changes are generally not found in planetary boundary layer height and precipitation.Citation: Murazaki, K., and P. Hess (2006), How does climate change contribute to surface ozone change over the United States?,

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“…() noted the relative strengthening of amplitude with increase in intensity of hourly precipitation events over the central and eastern United States. Hu () showed a multi‐decadal variation in the diurnal rainfall pattern in the central United States, with the decades characterized by the southerly flow witnessing a rainfall peak in the midnight hour, and the decades with weakened southerly flow having a broad plateau of rainfall in the late night/early morning hours. On the basis of hourly rain record, the geographically varied characteristics of diurnal variation of the warm‐season precipitation events over mainland China were analyzed and summarized by Yu et al .…”

Section: Introductionmentioning

confidence: 99%

Spatial and diurnal characteristics of summer rainfall over Beijing Municipality based on a high-density AWS dataset

Yang¹,

Ren

Hou

et al. 2012

Int. J. Climatol.

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ABSTRACT:On basis of quality-control of hourly rainfall dataset of Automatic Weather Stations (AWSs) for the last 4 years (2007)(2008)(2009)(2010), the spatial and diurnal characteristics of summer rainfall in Beijing Municipality (BJM) is analyzed. Results show that the short-duration heavy rainfall events dominate summer rainfall in the study area. Rainfall events with 1-3 h duration make a large contribution to both frequency and amount of summer rainfall, and the total rainfall amount in summer fall almost in the events with duration less than 6 h. Two peaks in diurnal variation of rainfall event frequency are evident, with one in early morning and another in later evening, but only one peak in later evening occurs for diurnal variation of rainfall amount. The exact timing and magnitudes of the peaks vary from one station to another probably due to the influence of the complicated terrains and geographical conditions. Except for the southeast area of the BJM, however, the highest frequency of rainfall events always occurs in evening between 1900 and 2300 (Local Standard Time, or LST), almost consistent to the occurrence time of the maximum rainfall amount. The peak of rainfall event frequency over the southeast area is generally in early morning (0300-0500 LST) which might have been related to the combined influences from land-sea breeze and urbanization.

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A Multidecadal Variation in Summer Season Diurnal Rainfall in the Central United States*

Cited by 18 publications

References 11 publications

An Analysis of the Warm-Season Diurnal Cycle over the Continental United States and Northern Mexico in General Circulation Models

An Analysis of the Warm-Season Diurnal Cycle over the Continental United States and Northern Mexico in General Circulation Models

How does climate change contribute to surface ozone change over the United States?

Spatial and diurnal characteristics of summer rainfall over Beijing Municipality based on a high-density AWS dataset

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