scholarly journals Flooding in Western Washington: The Connection to Atmospheric Rivers*

2011 ◽  
Vol 12 (6) ◽  
pp. 1337-1358 ◽  
Author(s):  
Paul J. Neiman ◽  
Lawrence J. Schick ◽  
F. Martin Ralph ◽  
Mimi Hughes ◽  
Gary A. Wick
Keyword(s):  
Water Vapor ◽  
Heavy Precipitation ◽  
Meteorological Conditions ◽  
The Other ◽  
Close Link ◽  
Atmospheric Rivers ◽  
Low Level ◽  
Daily Streamflow ◽  
Western Washington ◽  
Streamflow Data

Abstract This study utilizes multiple decades of daily streamflow data gathered in four major watersheds in western Washington to determine the meteorological conditions most likely to cause flooding in those watersheds. Two are located in the Olympic Mountains and the other two in the western Cascades; and each has uniquely different topographic characteristics. The flood analysis is based on the maximum daily flow observed during each water year (WY) at each site [i.e., the annual peak daily flow (APDF)], with an initial emphasis on the 12 most recent water years between WY1998 and 2009, and then focusing on a 30-year interval between WY1980 and 2009. The shorter time period coincides with relatively complete passive microwave satellite coverage of integrated water vapor (IWV) over the Pacific basin. The combination of IWV imagery and streamflow data highlights a close link between landfalling atmospheric rivers (ARs) and APDFs (i.e., 46 of the 48 APDFs occurred with landfalling ARs). To complement this approach, the three-decade time series of APDFs, which correspond to the availability of the North American Regional Reanalysis (NARR) dataset, are examined. The APDFs occur most often, and are typically largest in magnitude, from November to January. The NARR is used to assess the composite meteorological conditions associated with the 10 largest APDFs at each site during this 30-year period. Heavy precipitation fell during the top 10 APDFs, and anomalously high composite NARR melting levels averaged ~1.9 km MSL, which is primarily above the four basins of interest. Hence, on average, mostly rain rather than snow fell within these basins, leading to enhanced runoff. The flooding on the four watersheds shared common meteorological attributes, including the presence of landfalling ARs with anomalous warmth, strong low-level water vapor fluxes, and weak static stability. There were also key differences that modulated the orographic control of precipitation. Notably, two watersheds experienced their top 10 APDFs when the low-level flow was southwesterly, while the other two basins had their largest APDFs with west–southwesterly flow. These differences arose because of the region’s complex topography, basin orientations, and related rain shadowing.

scholarly journals Tracking an Atmospheric River in a Warmer Climate: from Water Vapor to Economic Impacts

2017 ◽  
Author(s):  
Francina Dominguez ◽  
Sandy Dall'erba ◽  
Shuyi Huang ◽  
Andre Avelino ◽  
Ali Mehran ◽  
...  
Keyword(s):  
Water Vapor ◽  
Economic Impacts ◽  
Heavy Precipitation ◽  
Integrated Modeling ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Economic Losses ◽  
Radiative Forcings ◽  
Hypothetical Scenario ◽  
Western Washington

Abstract. Atmospheric rivers (ARs) account for more than 75 % of heavy precipitation events and nearly all of the extreme flooding events along the Olympic Mountains and western Cascade mountains of western Washington state. In a warmer climate, ARs in this region are projected to become more frequent and intense, primarily due to increases in atmospheric water vapor. However, it is unclear how the changes in water vapor transport will affect regional flooding and associated economic impacts. In this work, we present an integrated modeling system to quantify the atmospheric-hydrologic-hydraulic and economic impacts of the December 2007 AR event that impacted the Chehalis river basin in western Washington. We use the modeling system to project impacts under a hypothetical scenario where the same December 2007 event occurs in a warmer climate. This method allows us to incorporate different types of uncertainty including: a) alternative future radiative forcings, b) different responses of the climate system to future radiative forcings and c) different responses of the surface hydrologic system. In the warming scenario, AR integrated vapor transport increases, however, these changes do not translate into generalized increases in precipitation throughout the basin. The changes in precipitation translate into spatially heterogeneous changes in sub-basin runoff and increased streamflow along the entire Chehalis main stem. Economic losses due to stock damages increased moderately, but losses in terms of business interruption were significant. Our integrated modeling tool provides communities in the Chehalis region with a range of possible future physical and economic impacts associated with AR flooding.

scholarly journals Forecasting Atmospheric Rivers during CalWater 2015

2017 ◽  
Vol 98 (3) ◽  
pp. 449-459 ◽  
Author(s):  
Jason M. Cordeira ◽  
F. Martin Ralph ◽  
Andrew Martin ◽  
Natalie Gaggini ◽  
J. Ryan Spackman ◽  
...  
Keyword(s):  
Water Vapor ◽  
West Coast ◽  
Heavy Precipitation ◽  
Field Studies ◽  
Field Phase ◽  
Forecast System ◽  
Field Campaign ◽  
Atmospheric Rivers ◽  
Vapor Flux ◽  
The U.S

Abstract Atmospheric rivers (ARs) are long and narrow corridors of enhanced vertically integrated water vapor (IWV) and IWV transport (IVT) within the warm sector of extra tropical cyclones that can produce heavy precipitation and flooding in regions of complex terrain, especially along the U.S. West Coast. Several field campaigns have investigated ARs under the CalWater program of field studies. The first field phase of CalWater during 2009–11 increased the number of observations of precipitation and aerosols, among other parameters, across California and sampled ARs in the coastal and near-coastal environment, whereas the second field phase of CalWater during 2014–15 observed the structure and intensity of ARs and aerosols in the coastal and offshore environment over the northeast Pacific. This manuscript highlights the forecasts that were prepared for the CalWater field campaign in 2015, and the development and use of an “AR portal” that was used to inform these forecasts. The AR portal contains archived and real-time deterministic and probabilistic gridded forecast tools related to ARs that emphasize water vapor concentrations and water vapor flux distributions over the eastern North Pacific, among other parameters, in a variety of formats derived from the National Centers for Environmental Prediction (NCEP) Global Forecast System and Global Ensemble Forecast System. The tools created for the CalWater 2015 field campaign provided valuable guidance for flight planning and field activity purposes, and they may prove useful in forecasting ARs and better anticipating hydrometeorological extremes along the U.S. West Coast.

scholarly journals Understanding the Role of Atmospheric Rivers in Heavy Precipitation in the Southeast United States

2016 ◽  
Vol 144 (4) ◽  
pp. 1617-1632 ◽  
Author(s):  
Kelly Mahoney ◽  
Darren L. Jackson ◽  
Paul Neiman ◽  
Mimi Hughes ◽  
Lisa Darby ◽  
...  
Keyword(s):  
United States ◽  
Seasonal Variation ◽  
Water Vapor ◽  
Heavy Precipitation ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Southeast United States ◽  
Atmospheric Rivers ◽  
Detection Tool ◽  
Match Rate

Abstract An analysis of atmospheric rivers (ARs) as defined by an automated AR detection tool based on integrated water vapor transport (IVT) and the connection to heavy precipitation in the southeast United States (SEUS) is performed. Climatological water vapor and water vapor transport fields are compared between the U.S. West Coast (WCUS) and the SEUS, highlighting stronger seasonal variation in integrated water vapor in the SEUS and stronger seasonal variation in IVT in the WCUS. The climatological analysis suggests that IVT values above ~500 kg m−1 s−1 (as incorporated into an objective identification tool such as the AR detection tool used here) may serve as a sensible threshold for defining ARs in the SEUS. Atmospheric river impacts on heavy precipitation in the SEUS are shown to vary on an annual cycle, and a connection between ARs and heavy precipitation during the nonsummer months is demonstrated. When identified ARs are matched to heavy precipitation days (>100 mm day−1), an average match rate of ~41% is found. Results suggest that some aspects of an AR identification framework in the SEUS may offer benefit in forecasting heavy precipitation, particularly at medium- to longer-range forecast lead times. However, the relatively high frequency of SEUS heavy precipitation cases in which an AR is not identified necessitates additional careful consideration and incorporation of other critical aspects of heavy precipitation environments such that significant predictive skill might eventually result.

scholarly journals Tracking an atmospheric river in a warmer climate: from water vapor to economic impacts

2018 ◽  
Vol 9 (1) ◽  
pp. 249-266 ◽  
Author(s):  
Francina Dominguez ◽  
Sandy Dall'erba ◽  
Shuyi Huang ◽  
Andre Avelino ◽  
Ali Mehran ◽  
...  
Keyword(s):  
Water Vapor ◽  
Economic Impacts ◽  
Heavy Precipitation ◽  
Integrated Modeling ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Economic Losses ◽  
Radiative Forcings ◽  
Hypothetical Scenario ◽  
Western Washington

Abstract. Atmospheric rivers (ARs) account for more than 75 % of heavy precipitation events and nearly all of the extreme flooding events along the Olympic Mountains and western Cascade Mountains of western Washington state. In a warmer climate, ARs in this region are projected to become more frequent and intense, primarily due to increases in atmospheric water vapor. However, it is unclear how the changes in water vapor transport will affect regional flooding and associated economic impacts. In this work we present an integrated modeling system to quantify the atmospheric–hydrologic–hydraulic and economic impacts of the December 2007 AR event that impacted the Chehalis River basin in western Washington. We use the modeling system to project impacts under a hypothetical scenario in which the same December 2007 event occurs in a warmer climate. This method allows us to incorporate different types of uncertainty, including (a) alternative future radiative forcings, (b) different responses of the climate system to future radiative forcings and (c) different responses of the surface hydrologic system. In the warming scenario, AR integrated vapor transport increases; however, these changes do not translate into generalized increases in precipitation throughout the basin. The changes in precipitation translate into spatially heterogeneous changes in sub-basin runoff and increased streamflow along the entire Chehalis main stem. Economic losses due to stock damages increase moderately, but losses in terms of business interruption are significant. Our integrated modeling tool provides communities in the Chehalis region with a range of possible future physical and economic impacts associated with AR flooding.

scholarly journals Atmospheric Rivers over the Northwestern Pacific: Climatology and Interannual Variability

2017 ◽  
Vol 30 (15) ◽  
pp. 5605-5619 ◽  
Author(s):  
Youichi Kamae ◽  
Wei Mei ◽  
Shang-Ping Xie ◽  
Moeka Naoi ◽  
Hiroaki Ueda
Keyword(s):  
Water Vapor ◽  
Interannual Variability ◽  
El Niño ◽  
El Nino ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Boreal Summer ◽  
Northwestern Pacific ◽  
Atmospheric Rivers ◽  
Low Level

Atmospheric rivers (ARs), conduits of intense water vapor transport in the midlatitudes, are critically important for water resources and heavy rainfall events over the west coast of North America, Europe, and Africa. ARs are also frequently observed over the northwestern Pacific (NWP) during boreal summer but have not been studied comprehensively. Here the climatology, seasonal variation, interannual variability, and predictability of NWP ARs (NWPARs) are examined by using a large ensemble, high-resolution atmospheric general circulation model (AGCM) simulation and a global atmospheric reanalysis. The AGCM captures general characteristics of climatology and variability compared to the reanalysis, suggesting a strong sea surface temperature (SST) effect on NWPARs. The summertime NWPAR occurrences are tightly related to El Niño–Southern Oscillation (ENSO) in the preceding winter through Indo–western Pacific Ocean capacitor (IPOC) effects. An enhanced East Asian summer monsoon and a low-level anticyclonic anomaly over the tropical western North Pacific in the post–El Niño summer reinforce low-level water vapor transport from the tropics with increased occurrence of NWPARs. The strong coupling with ENSO and IPOC indicates a high predictability of anomalous summertime NWPAR activity.

BIOCHEMICAL STUDIES ON SOCKEYE SALMON DURING SPAWNING MIGRATION: IV. THE NON-PROTEIN NITROGENOUS CONSTITUENTS OF THE MUSCLE

1958 ◽  
Vol 36 (8) ◽  
pp. 833-838 ◽  
Author(s):  
J. D. Wood
Keyword(s):  
Sockeye Salmon ◽  
The Other ◽  
Spawning Migration ◽  
Female Fish ◽  
Male And Female ◽  
Low Level ◽  
Early Stages ◽  
Biochemical Studies

The non-protein nitrogenous constituents of muscle of migrating sockeye salmon were investigated. These constituents were found to be the same in both male and female fish and were present in approximately the same amounts in both sexes. The histidine content of the muscle in all fish decreased to one fifth of the original value during the early stages of the migratory journey and remained at the low level thereafter. Some of the other constituents changed to a smaller extent, usually increasing in the later stages of the migration. This was especially noticeable in female fish. However, the increase in the concentration of these constituents in the muscle was due to a decrease in the amount of muscle in the fish rather than to an increase in the amounts of the compounds themselves.

scholarly journals The role of climatic and terrain attributes in estimating baseflow recession in tropical catchments

2010 ◽  
Vol 14 (11) ◽  
pp. 2193-2205 ◽  
Author(s):  
J. L. Peña-Arancibia ◽  
A. I. J. M. van Dijk ◽  
M. Mulligan ◽  
L. A. Bruijnzeel
Keyword(s):  
Potential Evapotranspiration ◽  
Aridity Index ◽  
Global Scale ◽  
Tree Cover ◽  
Annual Rainfall ◽  
Ungauged Catchments ◽  
Ongoing Research ◽  
Daily Streamflow ◽  
Terrain Attributes ◽  
Streamflow Data

Abstract. The understanding of low flows in rivers is paramount more than ever as demand for water increases on a global scale. At the same time, limited streamflow data to investigate this phenomenon, particularly in the tropics, makes the provision of accurate estimations in ungauged areas an ongoing research need. This paper analysed the potential of climatic and terrain attributes of 167 tropical and sub-tropical unregulated catchments to predict baseflow recession rates. Daily streamflow data (m3 s–1) from the Global River Discharge Center (GRDC) and a linear reservoir model were used to obtain baseflow recession coefficients (kbf) for these catchments. Climatic attributes included annual and seasonal indicators of rainfall and potential evapotranspiration. Terrain attributes included indicators of catchment shape, morphology, land cover, soils and geology. Stepwise regression was used to identify the best predictors for baseflow recession coefficients. Mean annual rainfall (MAR) and aridity index (AI) were found to explain 49% of the spatial variation of kbf. The rest of climatic indices and the terrain indices average catchment slope (SLO) and tree cover were also good predictors, but co-correlated with MAR. Catchment elongation (CE), a measure of catchment shape, was also found to be statistically significant, although weakly correlated. An analysis of clusters of catchments of smaller size, showed that in these areas, presumably with some similarity of soils and geology due to proximity, residuals of the regression could be explained by SLO and CE. The approach used provides a potential alternative for kbf parameterisation in ungauged catchments.

Aircraft Applications of Insecticides in East Africa. IV.—The Application of Coarse Aerosols in Savannah Woodland containing the Tsetse Flies Glossina morsitans and G. swynnertoni

1953 ◽  
Vol 44 (4) ◽  
pp. 627-640 ◽  
Author(s):  
K. S. Hocking ◽  
H. C. M. Parr ◽  
D. Yeo ◽  
D. Anstey
Keyword(s):  
East Africa ◽  
Meteorological Conditions ◽  
The Other ◽  
Tsetse Flies ◽  
Small Populations ◽  
Central Province ◽  
Glossina Morsitans ◽  
Short Period ◽  
Savannah Woodland ◽  
Mass Median

Attempts have been made to eradicate the tsetse flies G. morsitans and G. swynnertoni from two blocks of savannah woodland situated in the Central Province of Tanganyika.The insecticides were applied from aircraft. Coarse aerosols were used, with mass median diameters of approximately 90 microns; droplet diameters varied from 4 microns to 250 microns approximately.Eight applications of insecticides were made at intervals of two weeks. Each application was carried out at a nominal dosage of 0·25 gallons per acre, which was equivalent to 0·20 1b. per acre of the p, p'isomer of DDT or 0·03 lb. per acre of the γ isomer of BHC.In the area treated with DDT it is possible that both species of flies were eradicated for a short period, but small populations were re-established there by immigrant flies. In the other block the reduction was not so great, but it is not considered that this was due to a lesser effectiveness of the BHC, but to a combination of circumstances that led to less effective applications.Some general observations are made upon the use of aircraft for this sort of work, particularly in connection with the effect of meteorological conditions.

scholarly journals The effects of aerosols on precipitation and dimensions of subtropical clouds: a sensitivity study using a numerical cloud model

2006 ◽  
Vol 6 (1) ◽  
pp. 67-80 ◽  
Author(s):  
A. Teller ◽  
Z. Levin
Keyword(s):  
Water Vapor ◽  
Climate Models ◽  
Cloud Model ◽  
Cloud Condensation Nuclei ◽  
Sensitivity Study ◽  
Meteorological Conditions ◽  
Dust Particles ◽  
Noticeable Effect ◽  
Convective Clouds ◽  
Ice Nuclei

Abstract. Numerical experiments were carried out using the Tel-Aviv University 2-D cloud model to investigate the effects of increased concentrations of Cloud Condensation Nuclei (CCN), giant CCN (GCCN) and Ice Nuclei (IN) on the development of precipitation and cloud structure in mixed-phase sub-tropical convective clouds. In order to differentiate between the contribution of the aerosols and the meteorology, all simulations were conducted with the same meteorological conditions. The results show that under the same meteorological conditions, polluted clouds (with high CCN concentrations) produce less precipitation than clean clouds (with low CCN concentrations), the initiation of precipitation is delayed and the lifetimes of the clouds are longer. GCCN enhance the total precipitation on the ground in polluted clouds but they have no noticeable effect on cleaner clouds. The increased rainfall due to GCCN is mainly a result of the increased graupel mass in the cloud, but it only partially offsets the decrease in rainfall due to pollution (increased CCN). The addition of more effective IN, such as mineral dust particles, reduces the total amount of precipitation on the ground. This reduction is more pronounced in clean clouds than in polluted ones. Polluted clouds reach higher altitudes and are wider than clean clouds and both produce wider clouds (anvils) when more IN are introduced. Since under the same vertical sounding the polluted clouds produce less rain, more water vapor is left aloft after the rain stops. In our simulations about 3.5 times more water evaporates after the rain stops from the polluted cloud as compared to the clean cloud. The implication is that much more water vapor is transported from lower levels to the mid troposphere under polluted conditions, something that should be considered in climate models.

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