scholarly journals Precipitation Recycling Variability and Ecoclimatological Stability—A Study Using NARR Data. Part II: North American Monsoon Region

2008 ◽  
Vol 21 (20) ◽  
pp. 5187-5203 ◽  
Author(s):  
Francina Dominguez ◽  
Praveen Kumar ◽  
Enrique R. Vivoni

Abstract This work studies precipitation recycling as part of the dynamic North American monsoon system (NAMS) to understand how moisture and energy fluxes modulate recycling variability at the daily-to-intraseasonal time scale. A set of land–atmosphere variables derived from North American Regional Reanalysis (NARR) data are used to represent the hydroclimatology of the monsoon. The recycling ratio is estimated using the Dynamic Recycling Model, which provides recycling estimates at the daily time scales. Multichannel singular spectrum analysis (M-SSA) is used to extract trends in the data while at the same time selecting only the variability common to all of the variables. The 1985–2006 climatological analysis of NAMS precipitation recycling reveals a positive feedback mechanism between monsoon precipitation and subsequent increase in precipitation of recycled origin. Recycling ratios during the monsoon are consistently above 15% and can be as high as 25%. While monsoon precipitation and evapotranspiration are predominantly located in the seasonally dry tropical forests in the southwestern part of the domain, recycling is enhanced northeast of this region, indicating a relocation of soil moisture farther inland to drier regions in the northeast. The three years with the longest monsoons in the 22-yr period present an asynchronous pattern between precipitation and recycling ratio. The longest monsoons have a characteristic double peak in precipitation, with enhanced recycling ratios during the intermediate dry period. This indicates that, even when large-scale moisture advection decreases, evapotranspiration provides moisture to the overlying atmosphere, contributing to precipitation. Through the negative feedback present during long monsoons and by relocation of soil moisture, precipitation recycling brings favorable conditions for vegetation sustenance in the NAMS region.

Ecohydrology ◽  
2008 ◽  
Vol 1 (3) ◽  
pp. 225-238 ◽  
Author(s):  
Enrique R. Vivoni ◽  
Alex J. Rinehart ◽  
Luis A. Méndez-Barroso ◽  
Carlos A. Aragón ◽  
Gautam Bisht ◽  
...  

2008 ◽  
Vol 35 (22) ◽  
Author(s):  
Enrique R. Vivoni ◽  
Hernan A. Moreno ◽  
Giuseppe Mascaro ◽  
Julio C. Rodriguez ◽  
Christopher J. Watts ◽  
...  

2016 ◽  
Vol 17 (12) ◽  
pp. 2981-2995 ◽  
Author(s):  
Alex Mahalov ◽  
Jialun Li ◽  
Peter Hyde

Abstract In this study, the impacts of Mexican and southwestern U.S. agricultural and urban irrigation on North American monsoon (NAM) rainfall and other hydrometeorological fields are investigated using the Weather Research and Forecasting (WRF) Model by implementing an irrigation scheme into the WRF–land surface model. Taking the 2000–12 monsoon seasons as examples, multiple WRF simulations with irrigation are conducted by designing different crops’ maximum allowable water depletions (SWm). In comparison with gridded rainfall observations in urban and rural area, the WRF simulations with/without irrigation generally capture the observations very well, but with underestimation along the western slope of the Sierra Madre Occidental (SMO) and overestimation over southern Mexico. The simulations of WRF with irrigation are slightly improved over those without irrigation, compared with rainfall and sounding observations. Sensitivity studies reveal that the impact of irrigation on rainfall varies with location and NAM rainfall variability. Irrigation increases rainfall in eastern Arizona–western New Mexico and in northwestern Mexico because of the irrigation-induced increases of convective available potential energy (CAPE) and precipitable water. Overall, irrigation decreases rainfall in western Arizona, along the western slope of the SMO, and in central Mexico because of irrigation-induced increases of convective inhibition (CIN), decreases of CAPE, and/or large-scale water vapor divergence.


2013 ◽  
Vol 26 (22) ◽  
pp. 8787-8801 ◽  
Author(s):  
Kerrie L. Geil ◽  
Yolande L. Serra ◽  
Xubin Zeng

Abstract Precipitation, geopotential height, and wind fields from 21 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are examined to determine how well this generation of general circulation models represents the North American monsoon system (NAMS). Results show no improvement since CMIP3 in the magnitude (root-mean-square error and bias) of the mean annual cycle of monthly precipitation over a core monsoon domain, but improvement in the phasing of the seasonal cycle in precipitation is notable. Monsoon onset is early for most models but is clearly visible in daily climatological precipitation, whereas monsoon retreat is highly variable and unclear in daily climatological precipitation. Models that best capture large-scale circulation patterns at a low level usually have realistic representations of the NAMS, but even the best models poorly represent monsoon retreat. Difficulty in reproducing monsoon retreat results from an inaccurate representation of gradients in low-level geopotential height across the larger region, which causes an unrealistic flux of low-level moisture from the tropics into the NAMS region that extends well into the postmonsoon season. Composites of the models with the best and worst representations of the NAMS indicate that adequate representation of the monsoon during the early to midseason can be achieved even with a large-scale circulation pattern bias, as long as the bias is spatially consistent over the larger region influencing monsoon development; in other words, as with monsoon retreat, it is the inaccuracy of the spatial gradients in geopotential height across the larger region that prevents some models from realistic representation of the early and midseason monsoon system.


Author(s):  
Andreas P. Wion ◽  
Ian S. Pearse ◽  
Kyle C. Rodman ◽  
Thomas T. Veblen ◽  
Miranda D. Redmond

We aimed to disentangle the patterns of synchronous and variable cone production (i.e. masting) and its relationship to climate in two conifer species native to dry forests of western North America. We used cone abscission scars to reconstruct ca 15 years of recent cone production in Pinus edulis and Pinus ponderosa , and used redundancy analysis to relate time series of annual cone production to climate indices describing the North American monsoon and the El Niño Southern Oscillation (ENSO). We show that the sensitivity to climate and resulting synchrony in cone production varies substantially between species. Cone production among populations of P. edulis was much more spatially synchronous and more closely related to large-scale modes of climate variability than among populations of P. ponderosa . Large-scale synchrony in P. edulis cone production was associated with the North American monsoon and we identified a dipole pattern of regional cone production associated with ENSO phase. In P. ponderosa , these climate indices were not strongly associated with cone production, resulting in asynchronous masting patterns among populations. This study helps frame our understanding of mast seeding as a life-history strategy and has implications for our ability to forecast mast years in these species. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.


2019 ◽  
Vol 32 (23) ◽  
pp. 8355-8372 ◽  
Author(s):  
Arianna M. Varuolo-Clarke ◽  
Kevin A. Reed ◽  
Brian Medeiros

Abstract This work examines the effect of horizontal resolution and topography on the North American monsoon (NAM) in experiments with an atmospheric general circulation model. Observations are used to evaluate the fidelity of the representation of the monsoon in simulations from the Community Atmosphere Model version 5 (CAM5) with a standard 1.0° grid spacing and a high-resolution 0.25° grid spacing. The simulated monsoon has some realistic features, but both configurations also show precipitation biases. The default 1.0° grid spacing configuration simulates a monsoon with an annual cycle and intensity of precipitation within the observational range, but the monsoon begins and ends too gradually and does not reach far enough north. This study shows that the improved representation of topography in the high-resolution (0.25° grid spacing) configuration improves the regional circulation and therefore some aspects of the simulated monsoon compared to the 1.0° counterpart. At higher resolution, CAM5 simulates a stronger low pressure center over the American Southwest, with more realistic low-level wind flow than in the 1.0° configuration. As a result, the monsoon precipitation increases as does the amplitude of the annual cycle of precipitation. A moisture analysis sheds light on the monsoon dynamics, indicating that changes in the advection of enthalpy and moist static energy drive the differences between monsoon precipitation in CAM5 1.0° compared to the 0.25° configuration. Additional simulations confirm that these improvements are mainly due to the topographic influence on the low-level flow through the Gulf of California, and not only the increase in horizontal resolution.


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