scholarly journals Evaluation of Oceanic and Terrestrial Sources of Moisture for the North American Monsoon Using Numerical Models and Precipitation Stable Isotopes

2015 ◽  
Vol 16 (1) ◽  
pp. 19-35 ◽  
Author(s):  
Huancui Hu ◽  
Francina Dominguez
Keyword(s):  
Stable Isotopes ◽  
Gulf Of Mexico ◽  
Central America ◽  
North American ◽  
Gulf Of California ◽  
Caribbean Sea ◽  
Tropical Pacific ◽  
North American Monsoon ◽  
Moisture Sources ◽  
Source Regions

Abstract This work evaluates the oceanic and terrestrial moisture sources that contribute to North American monsoon (NAM) precipitation over a 30-yr period using the modified analytical dynamic recycling model. This computationally efficient modeling framework reveals previously overlooked moisture source regions such as Central America and the Caribbean Sea in addition to the well-known Gulf of California and Gulf of Mexico source regions. The results show that terrestrial evapotranspiration is as important as oceanic evaporation for NAM precipitation, and terrestrial sources contribute to approximately 40% of monsoonal moisture. There is a northward progression of terrestrial moisture sources, beginning with Central America during the early season and transitioning north into northern Mexico and the NAM region itself during the peak of the monsoon season. The most intense precipitation occurs toward the end of the season and tends to originate in the Gulf of California and the tropical Pacific, associated with tropical cyclones and gulf surges. Heavy stable isotopes of hydrogen and oxygen in precipitation (δD and δ18O) collected for every precipitation event measured in Tucson, Arizona, for the period 1981–2008 complement the numerical results. The analysis shows that precipitation events linked to sources from the Gulf of Mexico and Caribbean Sea are more isotopically enriched than sources from the Gulf of California and tropical Pacific. It is also seen that terrestrial regions that derive their precipitation from the Gulf of Mexico are also more isotopically enriched than moisture sources from the Pacific.

scholarly journals On the origin of moisture related to synoptic-scale rainfall events for the North American Monsoon System

2018 ◽  
Author(s):  
Paulina Ordoñez ◽  
Raquel Nieto ◽  
Yolande L. Serra ◽  
Luis Gimeno ◽  
Pedro Ribera ◽  
...  
Keyword(s):  
Water Vapor ◽  
Gulf Of Mexico ◽  
North American ◽  
Gulf Of California ◽  
Caribbean Sea ◽  
North American Monsoon ◽  
Synoptic Scale ◽  
Rainfall Events ◽  
The North ◽  
The Caribbean

Abstract. This work examines the origin of atmospheric water vapor arriving to the North American Monsoon (NAM) region over a 34-yr period (1981–2014) by using a Lagrangian diagnosis method. This methodology computes budgets of evaporation minus precipitation by calculating changes in the specific humidity of thousands of air particles advected into the study area by the observed winds. During the NAM wet season, on average the recycling process is the main water vapor source, followed by the supply of moisture from the Gulf of California. However, the water vapor transport that generates synoptic-scale rainfall comes primarily from the Caribbean Sea, the Gulf of Mexico and terrestrial eastern Mexico. An additional moisture source over the southwestern US is also identified in association with synoptic rainfall events over the NAM region. A high (low) moisture supply from the Caribbean Sea and the Gulf of Mexico from 4 to 6 days before precipitation events is responsible for high (low) rainfall intensity on synoptic scales during the monsoon peak. Westward propagating mid to upper level inverted troughs (IVs) seem to favor these water vapor fluxes. A 200 % increase in the moisture flux from the Caribbean Sea is related to the occurrence of heavy precipitation in the NAM area, accompanied by a decrease in water vapor advection from the Gulf of California.

scholarly journals Climatological moisture sources for the Western North American Monsoon through a Lagrangian approach: their influence on precipitation intensity

2019 ◽  
Vol 10 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Paulina Ordoñez ◽  
Raquel Nieto ◽  
Luis Gimeno ◽  
Pedro Ribera ◽  
David Gallego ◽  
...  
Keyword(s):  
Water Vapor ◽  
Gulf Of Mexico ◽  
North American ◽  
Regional Scale ◽  
Caribbean Sea ◽  
Lagrangian Approach ◽  
Specific Humidity ◽  
North American Monsoon ◽  
The Caribbean ◽  
Upper Level

Abstract. This work examines the origin of atmospheric water vapor arriving to the western North American monsoon (WNAM) region over a 34-year period (1981–2014) using a Lagrangian approach. This methodology computes budgets of evaporation minus precipitation (E−P) by calculating changes in the specific humidity of thousands of air particles advected into the study area by the observed winds. The length of the period analyzed (34 years) allows the method to identify oceanic and terrestrial sources of moisture to the WNAM region from a climatological perspective. During the wet season, the WNAM region itself is on average the main evaporative source, followed by the Gulf of California. However, water vapor originating from the Caribbean Sea, the Gulf of Mexico, and terrestrial eastern Mexico is found to influence regional-scale rainfall generation. Enhanced (reduced) moisture transport from the Caribbean Sea and the Gulf of Mexico from 4 to 6 days before precipitation events seems to be responsible for increased (decreased) rainfall intensity on regional scales during the monsoon peak. Westward propagating mid- to upper-level inverted troughs (IVs) seem to favor these water vapor fluxes from the east. In particular, a 200 % increase in the moisture flux from the Caribbean Sea to the WNAM region is found to be followed by the occurrence of heavy precipitation in the WNAM area a few days later. Low-level troughs off the coast of northwestern Mexico and upper-level IVs over the Gulf of Mexico are also related to these extreme rainfall events.

Hydrological changes and paleoproductivity in the Gulf of California during middle and late Holocene and their relationship with ITCZ and North American Monsoon variability

2013 ◽  
Vol 79 (2) ◽  
pp. 138-151 ◽  
Author(s):  
Ligia Pérez-Cruz
Keyword(s):  
North American ◽  
Gulf Of California ◽  
Late Holocene ◽  
Tropical Pacific ◽  
North American Monsoon ◽  
The North ◽  
Monsoon Variability ◽  
Monsoonal Precipitation ◽  
Central Atlantic ◽  
Middle And Late Holocene

AbstractThis study investigates changes in precipitation patterns and variations in paleoproductivity in the tropical Pacific region associated with the North American Monsoon, Intertropical Convergence Zone (ITCZ) latitudinal migration, and changes in insolation during the middle and late Holocene. Major and trace element records (Al, Ba, C, K, Si and Ti) and Zr/Al and Ba/Al ratios in a core from Alfonso Basin, southern Gulf of California, are used as proxies of terrigenous input and bio-productivity. Records reveal an increase in precipitation and low bio-productivity ca. 6200 to 2400 cal yr BP, associated with the strengthening of monsoonal precipitation and northward shift of the ITCZ mean position in the eastern tropical Pacific. A multi-centennial drought from ca. 2400 to 1900 cal yr BP, and a dry and cold interval ca. 700 and 500 cal yr BP, are characterized by strong aeolian input and enhanced productivity, associated with diminution of the summer monsoonal precipitation and reduced insolation in the Northern Hemisphere and more southerly ITCZ position. Correlation of Alfonso Basin records with other records in the Gulf of California and the Pigmy and Cariaco basins in the Gulf of Mexico and central Atlantic provides constraints on NAM, ITCZ migration, and insolation-driven changes.

scholarly journals The Effect of the MJO on the North American Monsoon*

2006 ◽  
Vol 19 (3) ◽  
pp. 333-343 ◽  
Author(s):  
David J. Lorenz ◽  
Dennis L. Hartmann
Keyword(s):  
North American ◽  
Gulf Of California ◽  
Tropical Pacific ◽  
North American Monsoon ◽  
Madden Julian Oscillation ◽  
Monsoon Precipitation ◽  
Easterly Waves ◽  
Northwest Mexico ◽  
The North ◽  
The Tropical Pacific

Abstract The effect of the Madden–Julian oscillation (MJO) in the eastern Pacific on the North American monsoon is documented using NCEP–NCAR reanalysis and daily mean precipitation data from 1958 to 2003. It is found that positive zonal wind anomalies in the eastern tropical Pacific lead to above-normal precipitation in northwest Mexico and Arizona from several days to over a week later. This connection between the tropical Pacific and monsoon precipitation appears to be limited to regions influenced by moisture surges from the Gulf of California as a similar connection does not exist for New Mexico precipitation. The evidence suggests that the MJO might affect monsoon precipitation by modulating the strength of low-level easterly waves off the coast of Mexico, which in turn triggers the development of a gulf surge.

scholarly journals A Numerical Investigation of Wet and Dry Onset Modes in the North American Monsoon Core Region. Part I: A Regional Mechanism for Interannual Variability

2012 ◽  
Vol 25 (11) ◽  
pp. 3953-3969 ◽  
Author(s):  
Cuauhtémoc Turrent ◽  
Tereza Cavazos
Keyword(s):  
Interannual Variability ◽  
Diurnal Cycle ◽  
North American ◽  
Gulf Of California ◽  
Deep Convection ◽  
Core Region ◽  
Eastern Pacific ◽  
North American Monsoon ◽  
The Core ◽  
The North

In this study the results of two regional fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) simulations forced at their boundaries with low-pass-filtered North American Regional Reanalysis (NARR) composite fields from which synoptic-scale variability was removed are presented. The filtered NARR data are also assimilated into the inner domain through the use of field nudging. The purpose of this research is to investigate wet and dry onset modes in the core region of the North American monsoon (NAM). Key features of the NAM that are present in the NARR fields and assimilated into the regional simulations include the position of the midlevel anticyclone, low-level circulation over the Gulf of California, and moisture flux patterns into the core monsoon region, for which the eastern Pacific is the likely primary source of moisture. The model develops a robust diurnal cycle of deep convection over the peaks of the Sierra Madre Occidental (SMO) that results solely from its radiation scheme and internal dynamics, in spite of the field nudging. The wet onset mode is related to a regional land–sea thermal contrast (LSTC) that is ~2°C higher than in the dry mode, and is further characterized by a northward-displaced midlevel anticyclone, a stronger surface pressure gradient along the Gulf of California, larger mean moisture fluxes into the core region from the eastern Pacific, a stronger diurnal cycle of deep convection, and the more northward distribution of precipitation along the axis of the SMO. A proposed regional LSTC mechanism for NAM onset interannual variability is consistent with the differences between both onset modes.

scholarly journals Modeling Intraseasonal Features of 2004 North American Monsoon Precipitation

2007 ◽  
Vol 20 (9) ◽  
pp. 1882-1896 ◽  
Author(s):  
X. Gao ◽  
J. Li ◽  
S. Sorooshian
Keyword(s):  
Time Scales ◽  
North American ◽  
Gulf Of California ◽  
Mesoscale Model ◽  
Numerical Study ◽  
North American Monsoon ◽  
Monthly Precipitation ◽  
Diurnal Variability ◽  
Late Night ◽  
Diagnostic Characteristics

Abstract This study examines the capabilities and limitations of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) in predicting the precipitation and circulation features that accompanied the 2004 North American monsoon (NAM). When the model is reinitialized every 5 days to restrain the growth of modeling errors, its results for precipitation checked at subseasonal time scales (not for individual rainfall events) become comparable with ground- and satellite-based observations as well as with the NAM’s diagnostic characteristics. The modeled monthly precipitation illustrates the evolution patterns of monsoon rainfall, although it underestimates the rainfall amount and coverage area in comparison with observations. The modeled daily precipitation shows the transition from dry to wet episodes on the monsoon onset day over the Arizona–New Mexico region, and the multiday heavy rainfall (>1 mm day−1) and dry periods after the onset. All these modeling predictions agree with observed variations. The model also accurately simulated the onset and ending dates of four major moisture surges over the Gulf of California during the 2004 monsoon season. The model reproduced the strong diurnal variability of the NAM precipitation, but did not predict the observed diurnal feature of the precipitation peak’s shift from the mountains to the coast during local afternoon to late night. In general, the model is able to reproduce the major, critical patterns and dynamic variations of the NAM rainfall at intraseasonal time scales, but still includes errors in precipitation quantity, pattern, and timing. The numerical study suggests that these errors are due largely to deficiencies in the model’s cumulus convective parameterization scheme, which is responsible for the model’s precipitation generation.

scholarly journals Multiscale Variability of the Flow during the North American Monsoon Experiment

2007 ◽  
Vol 20 (9) ◽  
pp. 1628-1648 ◽  
Author(s):  
Richard H. Johnson ◽  
Paul E. Ciesielski ◽  
Brian D. McNoldy ◽  
Peter J. Rogers ◽  
Richard K. Taft
Keyword(s):  
United States ◽  
North American ◽  
Gulf Of California ◽  
Large Scale ◽  
Regional Scale ◽  
North American Monsoon ◽  
Return Flow ◽  
Southwestern United States ◽  
The North ◽  
Upper Level

Abstract The 2004 North American Monsoon Experiment (NAME) provided an unprecedented observing network for studying the structure and evolution of the North American monsoon. This paper focuses on multiscale characteristics of the flow during NAME from the large scale to the mesoscale using atmospheric sounding data from the enhanced observing network. The onset of the 2004 summer monsoon over the NAME region accompanied the typical northward shift of the upper-level anticyclone or monsoon high over northern Mexico into the southwestern United States, but in 2004 this shift occurred slightly later than normal and the monsoon high did not extend as far north as usual. Consequently, precipitation over the southwestern United States was slightly below normal, although increased troughiness over the Great Plains contributed to increased rainfall over eastern New Mexico and western Texas. The first major pulse of moisture into the Southwest occurred around 13 July in association with a strong Gulf of California surge. This surge was linked to the westward passages of Tropical Storm Blas to the south and an upper-level inverted trough over northern Texas. The development of Blas appeared to be favored as an easterly wave moved into the eastern Pacific during the active phase of a Madden–Julian oscillation. On the regional scale, sounding data reveal a prominent sea breeze along the east shore of the Gulf of California, with a deep return flow as a consequence of the elevated Sierra Madre Occidental (SMO) immediately to the east. Subsidence produced a dry layer over the gulf, whereas a deep moist layer existed over the west slopes of the SMO. A prominent nocturnal low-level jet was present on most days over the northern gulf. The diurnal cycle of heating and moistening (Q1 and Q2) over the SMO was characterized by deep convective profiles in the mid- to upper troposphere at 1800 LT, followed by stratiform-like profiles at midnight, consistent with the observed diurnal evolution of precipitation over this coastal mountainous region. The analyses in the core NAME domain are based on a gridded dataset derived from atmospheric soundings only and, therefore, should prove useful in validating reanalyses and regional models.

scholarly journals A taxonomic account of species in the tribe Spongoclonieae (Ceramiaceae, Ceramiales, Rhodophyta) reported from Atlantic and Pacific Mexico

Phytotaxa ◽  
2018 ◽  
Vol 340 (3) ◽  
pp. 229
Author(s):  
LUZ ELENA MATEO-CID ◽  
A. CATALINA MENDOZA-GONZÁLEZ ◽  
JAMES N. NORRIS ◽  
DEISY Y. GARCÍA-LÓPEZ
Keyword(s):  
Gulf Of Mexico ◽  
Gulf Of California ◽  
New Records ◽  
Atlantic Coast ◽  
Single Species ◽  
Tropical Pacific ◽  
Reproductive Structures ◽  
Consistent Basis ◽  
Vegetative Characters ◽  
Mexican Species

The tribe Spongoclonieae (Ceramiaceae subfam. Spongoclonioideae) is represented on the Atlantic and Pacific coasts of Mexico by two genera: Pleonosporium with eight species and Spongoclonium with a single species. Pleonosporium boergesenii and P. borreri are both new records for Atlantic Mexico. Known in Pacific and Atlantic Mexico, P. rhizoideum has the widest distribution, while P. pygmaeum and P. vancouverianum have only a few records in the study area. Pleonosporium mexicanum is found mainly in tropical Pacific Mexico, and P. globuliferum has a discontinuous distribution in the Gulf of California and then in Salina Cruz, Oaxaca. In the case of P. squarrulosum morphological and genetic comparisons are needed to verify its presence in Mexico. The report of Spongoclonium caribaeum from intertidal Veracruz (Gulf of Mexico) represents the second record of this species for the Atlantic coast of Mexico. Detailed descriptions, information on nomenclature, collections studied, distribution and habitat are provided for each of the species. Measurements of vegetative characters and reproductive structures provide a consistent basis for identifying Atlantic and Pacific Mexican species of Pleonosporium and Spongoclonium.

scholarly journals Comments on “Regional Impacts of Irrigation in Mexico and the Southwestern United States on Hydrometeorological Fields in the North American Monsoon Region”

2018 ◽  
Vol 19 (2) ◽  
pp. 477-481 ◽  
Author(s):  
Theodore J. Bohn ◽  
Enrique R. Vivoni
Keyword(s):  
North American ◽  
Gulf Of California ◽  
Wrf Model ◽  
Summer Precipitation ◽  
Atmospheric Modeling ◽  
Irrigated Agriculture ◽  
North American Monsoon ◽  
Impact Surface ◽  
The North ◽  
The Impact

Abstract For their investigation of the impact of irrigated agriculture on hydrometeorological fields in the North American monsoon (NAM) region, Mahalov et al. used the Weather Research and Forecasting (WRF) Model to simulate weather over the NAM region in the summer periods of 2000 and 2012, with and without irrigation applied to the regional croplands. Unfortunately, while the authors found that irrigated agriculture may indeed influence summer precipitation, the magnitude, location, and seasonality of their irrigation inputs were substantially inaccurate because of 1) the assumption that pixels classified as “irrigated cropland” are irrigated during the summer and 2) an outdated land cover map that misrepresents known agricultural districts. The combined effects of these errors are 1) an overestimation of irrigated croplands by a factor of 3–10 along the coast of the Gulf of California and by a factor of 1.5 near the Colorado River delta and 2) a large underestimation of irrigation by a factor of 7–10 in Chihuahua, particularly in 2012. Given the sensitivity of the WRF simulations conducted by Mahalov et al. to the presence of irrigated agriculture, it is expected that the identified errors would significantly impact surface moisture and energy fluxes, resulting in noticeably different effects on precipitation. The authors suggest that the analysis of irrigation effects on precipitation using coupled land–atmospheric modeling systems requires careful specification of the spatiotemporal distribution of irrigated croplands.

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