Precipitable Water from GPS Zenith Delays Using North American Regional Reanalysis Meteorology

2013 ◽  
Vol 30 (3) ◽  
pp. 485-495 ◽  
Author(s):  
James D. Means ◽  
Daniel Cayan
Keyword(s):  
North American ◽  
Precipitable Water ◽  
North American Monsoon ◽  
The North ◽  
Global Positioning ◽  
North American Regional Reanalysis ◽  
A New Technique ◽  
Regional Reanalysis ◽  
Water Values ◽  
Height Data

Abstract Precipitable water or integrated water vapor can be obtained from zenith travel-time delays from global positioning system (GPS) signals if the atmospheric pressure and temperature at the GPS site is known. There have been more than 10 000 GPS receivers deployed as part of geophysics research programs around the world; but, unfortunately, most of these receivers do not have collocated barometers. This paper describes a new technique to use North American Regional Reanalysis pressure, temperature, and geopotential height data to calculate station pressures and surface temperature at the GPS sites. This enables precipitable water to be calculated at those sites using archived zenith delays. The technique has been evaluated by calculating altimeter readings at aviation routine weather report (METAR) sites and comparing them with reported altimeter readings. Additionally, the precipitable water values calculated using this method have been found to agree with SuomiNet GPS precipitable water, with RMS differences of 2 mm or less, and are also generally in agreement with radiosonde measurements of precipitable water. Applications of this technique are shown and are explored for different synoptic situations, including atmospheric-river-type baroclinic storms and the North American monsoon.

scholarly journals GPS Precipitable Water as a Diagnostic of the North American Monsoon in California and Nevada

2013 ◽  
Vol 26 (4) ◽  
pp. 1432-1444 ◽  
Author(s):  
James D. Means
Keyword(s):  
North American ◽  
Precipitable Water ◽  
Temporal Variations ◽  
Monsoon Onset ◽  
North American Monsoon ◽  
Water Index ◽  
The North ◽  
Upper Level ◽  
Regional Reanalysis ◽  
Water Values

Abstract Precipitable water derived from archived global positioning system (GPS) zenith travel-time delays is used to describe the seasonal and interannual variation of the North American monsoon in California and Nevada. A 3-hourly dataset of precipitable water from 2003 to 2009, for over 500 sites in California and Nevada using temperature and pressure interpolated from the North American Regional Reanalysis (NARR), is constructed to study the temporal and spatial extent of the North American monsoon in the desert regions of California and Nevada. The statistical distribution of precipitable water values is shown to delineate the region that is most often affected by the monsoonal influence. A normalized precipitable water index is employed to indicate when the monsoon starts and stops and to investigate spatial variability. The GPS network provides much higher spatial resolution than other meteorological networks using surface-based methods, such as dewpoint criteria and rainfall, and is seen to contain comparable ability in capturing temporal variations. This dataset reveals the northwestward propagation of the monsoon onset both synoptically and seasonally. The GPS observations indicate that in the mean the decay of the monsoon is less well defined than the onset. Seven-year reanalysis 700-mb geopotential height composites for the monsoon onset and 3 days prior indicate that the onset of the monsoon is associated with a shift in the synoptic pattern characterized by upper-level high pressure building from the east and offshore troughing retreating to the northwest.

scholarly journals Flow, Moisture, and Thermodynamic Variability Associated with Gulf of California Surges within the North American Monsoon

2012 ◽  
Vol 25 (12) ◽  
pp. 4220-4241 ◽  
Author(s):  
Nicole J. Schiffer ◽  
Stephen W. Nesbitt
Keyword(s):  
New Mexico ◽  
North American ◽  
Gulf Of California ◽  
Reanalysis Data ◽  
North American Monsoon ◽  
Air Masses ◽  
The North ◽  
Sierra Madre ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Abstract This study uses an improved surge identification method to examine composites of 29 yr of surface observations and reanalysis data alongside 10 yr of satellite precipitation data to reveal connections between flow, thermodynamic parameters, and precipitation, both within and outside of the North American monsoon (NAM) region, associated with Gulf of California (GoC) moisture surges. The North American Regional Reanalysis (NARR), examined using composites of flow during all detected moisture surges at Yuma, Arizona, and so-called wet and dry surges (those producing anomalously high and low precipitation, respectively, over Arizona and New Mexico), show markedly different flow and moisture patterns that ultimately lead to the differing observed precipitation distributions in the region. Wet surges tend to be associated with moister precursor air masses over the southwestern United States, have a larger contribution of enhanced easterly cross–Sierra Madre Occidental (SMO) moisture transport, and tend to result from a transient cyclonic disturbance tracking across northern Mexico. Dry surges tend to be associated with a more southerly tracking disturbance, are associated with less convection over the SMO, and tend to be associated with a drier presurge air mass over Arizona and New Mexico.

Spurious Grid-Scale Precipitation in the North American Regional Reanalysis

2007 ◽  
Vol 135 (6) ◽  
pp. 2168-2184 ◽  
Author(s):  
Gregory L. West ◽  
W. James Steenburgh ◽  
William Y. Y. Cheng
Keyword(s):  
North American ◽  
Prediction Models ◽  
Weather Prediction ◽  
Regional Climate ◽  
Potential Temperature ◽  
Climate Data ◽  
The North ◽  
North American Regional Reanalysis ◽  
Upper Level ◽  
Regional Reanalysis

Abstract Spurious grid-scale precipitation (SGSP) occurs in many mesoscale numerical weather prediction models when the simulated atmosphere becomes convectively unstable and the convective parameterization fails to relieve the instability. Case studies presented in this paper illustrate that SGSP events are also found in the North American Regional Reanalysis (NARR) and are accompanied by excessive maxima in grid-scale precipitation, vertical velocity, moisture variables (e.g., relative humidity and precipitable water), mid- and upper-level equivalent potential temperature, and mid- and upper-level absolute vorticity. SGSP events in environments favorable for high-based convection can also feature low-level cold pools and sea level pressure maxima. Prior to 2003, retrospectively generated NARR analyses feature an average of approximately 370 SGSP events annually. Beginning in 2003, however, NARR analyses are generated in near–real time by the Regional Climate Data Assimilation System (R-CDAS), which is identical to the retrospective NARR analysis system except for the input precipitation and ice cover datasets. Analyses produced by the R-CDAS feature a substantially larger number of SGSP events with more than 4000 occurring in the original 2003 analyses. An oceanic precipitation data processing error, which resulted in a reprocessing of NARR analyses from 2003 to 2005, only partially explains this increase since the reprocessed analyses still produce approximately 2000 SGSP events annually. These results suggest that many NARR SGSP events are not produced by shortcomings in the underlying Eta Model, but by the specification of anomalous latent heating when there is a strong mismatch between modeled and assimilated precipitation. NARR users should ensure that they are using the reprocessed NARR analyses from 2003 to 2005 and consider the possible influence of SGSP on their findings, particularly after the transition to the R-CDAS.

scholarly journals Hydroclimate and variability in the Great Lakes region as derived from the North American Regional Reanalysis

2010 ◽  
Vol 115 (D12) ◽  
Author(s):  
Xiuping Li ◽  
Shiyuan Zhong ◽  
Xindi Bian ◽  
Warren E. Heilman ◽  
Yong Luo ◽  
...  
Keyword(s):  
Great Lakes ◽  
North American ◽  
Great Lakes Region ◽  
The North ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

scholarly journals North American Supercell Environments in Atmospheric Reanalyses and RUC-2

2019 ◽  
Vol 58 (1) ◽  
pp. 71-92 ◽  
Author(s):  
Austin T. King ◽  
Aaron D. Kennedy
Keyword(s):  
North American ◽  
Grid Point ◽  
Convective Available Potential Energy ◽  
Kinematic Parameters ◽  
The North ◽  
Composite Parameter ◽  
Analysis Package ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis ◽  
Effective Layer

AbstractA suite of modern atmospheric reanalyses is analyzed to determine how they represent North American supercell environments. This analysis is performed by comparing a database of Rapid Update Cycle (RUC-2) proximity soundings with profiles derived from the nearest grid point in each reanalysis. Parameters are calculated using the Sounding and Hodograph Analysis and Research Program in Python (SHARPpy), an open-source Python sounding-analysis package. Representation of supercell environments varies across the reanalyses, and the results have ramifications for climatological studies that use these datasets. In particular, thermodynamic parameters such as the convective available potential energy (CAPE) show the widest range in biases, with reanalyses falling into two camps. The North American Regional Reanalysis (NARR) and the Japanese 55-year Reanalysis (JRA-55) are similar to RUC-2, but other reanalyses have a substantial negative bias. The reasons for these biases vary and range from thermodynamic biases at the surface to evidence of convective contamination. Overall, it is found that thermodynamic biases feed back to other convective parameters that incorporate CAPE directly or indirectly via the effective layer. As a result, significant negative biases are found for indices such as the supercell composite parameter. These biases are smallest for NARR and JRA-55. Kinematic parameters are more consistent across the reanalyses. Given the issues with thermodynamic properties, better segregation of soundings by storm type is found for fixed-layer parameters than for effective-layer shear parameters. Although no reanalysis can exactly reproduce the results of earlier RUC-2 studies, many of the reanalyses can broadly distinguish between environments that are significantly tornadic versus nontornadic.

scholarly journals Low-Level Jets in the North American Regional Reanalysis (NARR): A Comparison with Rawinsonde Observations

2014 ◽  
Vol 53 (9) ◽  
pp. 2093-2113 ◽  
Author(s):  
Claudia K. Walters ◽  
Julie A. Winkler ◽  
Sara Husseini ◽  
Ryan Keeling ◽  
Jovanka Nikolic ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
North American ◽  
Low Level ◽  
The North ◽  
Central United States ◽  
North American Regional Reanalysis ◽  
Low Level Jets ◽  
Regional Reanalysis ◽  
Wind Profiles ◽  
Fine Resolution

AbstractClimatological analyses of low-level jets (LLJs) can be negatively influenced by the coarse spatial and temporal resolution and frequent changes in observing and archiving protocols of rawinsonde observations (raobs). The introduction of reanalysis datasets, such as the North American Regional Reanalysis (NARR), provides new resources for climatological research with finer spatial and temporal resolution and potentially fewer inhomogeneities. To assess the compatibility of LLJ characteristics identified from NARR wind profiles with those obtained from raob profiles, LLJs were extracted using standard jet definitions from NARR and raobs at 12 locations in the central United States for four representative years that reflect different rawinsonde protocols. LLJ characteristics (e.g., between-station differences in relative frequency, diurnal fluctuations, and mean speed and elevation) are generally consistent, although absolute frequencies are smaller for NARR relative to raobs at most stations. LLJs are concurrently identified in the NARR and raob wind profiles on less than 60% of the observation times with LLJ activity. Variations are seen between analysis years and locations. Of particular note is the substantial increase in LLJ frequency seen in raobs since the introduction of the Radiosonde Replacement System, which has led to a greater discrepancy in jet frequency between the NARR and raob datasets. The analyses suggest that NARR is a viable additional resource for climatological analyses of LLJs. Many of the findings are likely applicable for other fine-resolution reanalysis datasets, although differences between reanalyses require that each be carefully evaluated before its use in climatological analyses of wind maxima.

scholarly journals Changing surface radiation and energy budgets of the Hudson Bay Complex using the North American regional reanalysis (NARR) model

2019 ◽  
Vol 5 (4) ◽  
pp. 218-239 ◽  
Author(s):  
Richard Bello ◽  
Kaz Higuchi
Keyword(s):  
North American ◽  
Surface Radiation ◽  
Energy Budgets ◽  
Hudson Bay ◽  
The North ◽  
Normal Period ◽  
Marine System ◽  
Annual Component ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Monthly and annual component fluxes of the surface radiation and energy budgets for the two-decade period from 1997 to 2016 are compared with the climate normal period (1981–2010) for the marine system consisting of James Bay, Hudson Bay, Hudson Strait and Foxe Basin using estimates from the North American regional reanalysis model. Reflected solar radiation has declined unevenly, primarily offshore of major rivers, in polynyas and along shore leads, both during earlier melt and later freeze up. Annually, net radiation increases are driven by albedo decreases during the summer. Over 94% of the increases in ocean heat gain during the melt season are due to increases in absorbed sunlight. Large enhanced oceanic heat losses in the late fall are almost entirely consumed by intensified convective losses of both sensible and latent heat. All the seas within the Hudson Bay Complex show a reduced rate of ocean warming over the past two decades. This outcome can be partially reconciled with the observation that all water bodies are experiencing enhanced losses of energy during extended ice-free winters that exceed enhanced gains of energy during the extended ice-free summers. The implications of seasonal changes in ice cover for future climate are discussed.

scholarly journals The North American Monsoon GPS Transect Experiment 2013

2016 ◽  
Vol 97 (11) ◽  
pp. 2103-2115 ◽  
Author(s):  
Yolande L. Serra ◽  
David K. Adams ◽  
Carlos Minjarez-Sosa ◽  
James M. Moker ◽  
Avelino F. Arellano ◽  
...  
Keyword(s):  
Water Vapor ◽  
North American ◽  
Water Cycle ◽  
Precipitable Water ◽  
Annual Rainfall ◽  
North American Monsoon ◽  
Atmospheric Sciences ◽  
The North ◽  
Northwestern Mexico ◽  
The Impact

Abstract Northwestern Mexico experiences large variations in water vapor on seasonal time scales in association with the North American monsoon, as well as during the monsoon associated with upper-tropospheric troughs, mesoscale convective systems, tropical easterly waves, and tropical cyclones. Together these events provide more than half of the annual rainfall to the region. A sufficient density of meteorological observations is required to properly observe, understand, and forecast the important processes contributing to the development of organized convection over northwestern Mexico. The stability of observations over long time periods is also of interest to monitor seasonal and longer-time-scale variability in the water cycle. For more than a decade, the U.S. Global Positioning System (GPS) has been used to obtain tropospheric precipitable water vapor (PWV) for applications in the atmospheric sciences. There is particular interest in establishing these systems where conventional operational meteorological networks are not possible due to the lack of financial or human resources to support the network. Here, we provide an overview of the North American Monsoon GPS Transect Experiment 2013 in northwestern Mexico for the study of mesoscale processes and the impact of PWV observations on high-resolution model forecasts of organized convective events during the 2013 monsoon. Some highlights are presented, as well as a look forward at GPS networks with surface meteorology (GPS-Met) planned for the region that will be capable of capturing a wider range of water vapor variability in both space and time across Mexico and into the southwestern United States.

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