New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/12 Physiography, climate, and vegetation of the Albuquerque region Roger Y. Anderson, 1961, pp. 63-71 in: Albuquerque Country, Northrop, S. A.; [ed.], New Mexico Geological Society 12th Annual Fall Field Conference Guidebook, 199 p. This is one of many related papers that were included in the 1961 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. 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One printed copy of any materials from the NMGS website or our print and electronic publications may be made for individual use without our permission. Teachers and students may make unlimited copies for educational use. Any other use of these materials requires explicit permission. This page is intentionally left blank to maintain order of facing pages. NEW MEXICO GEOLOGICAL SOCIETY TWELFTH FIELD CONFERENCE 63 PHYSIOGRAPHY, CLIMATE, AND VEGETATION OF THE ALBUQUERQUE REGION ROGER Y. ANDERSON University of New Mexico INTRODUCTION (4) Warm, moist Tropical Gulf from the Gulf of Varied physiographic features, a 6,800-foot difference Mexico and the Caribbean in elevation, several sources of atmospheric moisture and (5) Warm, moist Tropical Pacific from the southern directions of air mass movement combine to make the Pacific Ocean. climate, vegetation, and topography of the Albuquerque So many directions of air movement make weather pre- region interesting and complex. One can observe, first- diction in Albuquerque extremely difficult. Most of our hand, the intimate relationship between physiography, winter and spring moisture comes from the north Pacific precipitation, temperature, and vegetation and use the (type 2) although the source is so remote and so many region as a model for geomorphic and geologic interpre- mountain barriers intervene that only a little more than tation. 20 percent of the annual total is from this source. These PHYSIOGRAPHIC AREAS IN THE ALBUQUERQUE REGION air movements (storms) result in high-level moisture that A photographic copy of the Army Map Service plastic forms snow on the mountains, a little rain or snow at relief maps of the Albuquerque region gives an excellent intermediate elevations, and blowing dust at the lower over-all view of the major physiographic features (Fig. 2). elevations, particularly in the spring. About 65-70 percent For convenience, the region is divided into a number of of the annual total precipitation comes in the warm sea- structural-physiographic units (Fig. 1, modified from Kelley, son (April-September) from the Gulf of Mexico (type 4) 1952) and specific points of interest are designated by in the form of wandering convectional thunderstorms and numbers (i.e., 23). In the area covered by the photo- orographic thunderstorm buildups over the mountains. Both graphs, elevations range from 11,389 feet at Mount Tay- the North Pacific and the summer orographic storms re- lor Peak (39), 11,252 feet at Redondo Peak (3) in the lease most of their moisture in the mountains so that there Valles caldera, 10,685 feet at Sandia crest (17), and is a direct increase in precipitation with elevation, and a 10,120 feet at Manzano Peak (23) to about 4,800 feet precipitation map (Fig. 3) of the region is very nearly a at Belen in the southern part of the Belen-Albuquerque- topographic map as well. Santo Domingo Basin. Elevations rise to about 6,000 feet Movements of moist air from the Tropical Pacific at the northern end of this basin (8, 11, 14) and eleva- (type 5) add little to the annual rainfall although on rare tions of about 7,000-9,000 feet are found on some of occasions some of our longest and heaviest rains have come the higher mesas and cuestas of the Colorado Plateau and from that source. Interpretations of Pleistocene climate San Juan Basin areas (1, 42). and terrace formation are made difficult because of the unknown influence of this moisture source. Tropical Con- CLIMATE tinental (type 3) air usually results in warm dry weather Temperature and precipitation in the Albuquerque while in the winter months Polar Continental (type 1) air region are determined largely by local topography and sweeps down the east side of the State, resulting in ex- air mass movements from regions outside the State. The tended cold periods and some snow if warm moist air is mean annual temperature ranges from 57°F at the Albu- displaced. Tijeras Canyon presents the Albuquerque area querque Airport to 38°F at Sandia crest (17); the differ- with a local problem as the heavy, cold air, held back by ence in elevation is 5,365 feet. This gradient of about 1 °F the Sandia-Manzano Mountains, finds access to the basin for each 200-300-foot rise in elevation is the principal and literally pours through the canyon and spreads out controlling factor in the distribution of precipitation and on the "mesa" and valley below in gusts up to 50 miles vegetation, and, indirectly, in the physical appearance of per hour. the landforms. The mountain tops would be even colder were it not for the increase of wind velocity with elevation VEGETATION which tends to displace the normally cold air with warmer Early naturalists in the Southwest soon recognized air. The gradient is moderated somewhat in the deeper the remarkable correlation between vegetation and eleva- parts of the basins as the heavier cool air drains and tion and realized that under the influence of temperature settles at night after daytime convection stops. Low tem- and moisture availability the vertical changes corresponded, peratures in the Rio Grande valley are normally 8-10 in an approximate way, with latitudinal changes. Each degrees cooler than for the pediments and mesas, a 1,000-foot increase in elevation is about equivalent to a few hundred feet higher in elevation. The climate is 200-mile northward shift of latitude so that the type of decidedly continental with diurnal changes of 40°F. being plants found in Canada, such as spruce and fir, occur common. above 8,000 feet on mountains while plants typical of Air masses invade the Albuquerque region from five Mexico, such as mesquite and creosote bush, have extend- principal source areas as follows (Thornthwaite and others, ed their range up the Rio Grande valley as far north as 1942; Dorroh, 1946): the Rio Salado. This resulted in the formulation of the (1) Cold, dry Polar Continental from Canada and concept of life zones by Merriam (1890) and the naming northward of zones such as the Hudsonian, Canadian, and Sonoran (2) Cool, moist Polar Pacific from the north Paci- based on the vertical distribution of plant and animal life fic Ocean but using geographic terms to impart the idea of a rela- (3) Hot, dry Tropical Continental from Mexico and tionship to latitude. Later, ecologists found it necessary extreme southwest United States to refine the concept of life zones and classify character- s 41 42 40 MOUNT 38 TAY L7 ALBUQUERQUE \I/ -71C- SIERRA LADRON 28 27 S A N 26 A UGUSTIN PLAINS (C LOSED BASIN) Figure 1. Structural-physiographic areas and physiographic features in the Albuquerque region, New Mex- ico (modified from Kelley, 1952). NEW MEXICO GEOLOGICAL SOCIETY TWELFTH FIELD CONFERENCE 65 PHYSIOGRAPHIC FEATURES IN THE ALBUQUERQUE REGION istic plant and animal associations into biotic communities. The elevation tolerances for these biomes are as restric- 1. Chacra Mesa (elev. circa 7,000 feet) tive as those of life zones. Hoff (1959) has suggested 2. Pajarito Peak in Nacimiento Mts. (elev. circa 9,000 elevation ranges for the plant and animal associations in feet) New Mexico and has related them to life zones (Fig. 5). 3. Redondo Peak in Valles caldera (elev. 11,252 feet) The Arctic zone or Alpine Tundra association does 4. Sierra de Los Valles (elev. circa 10,000 feet) not occur on Mount Taylor, the Jemez Mountains, or the 5. Pajarito Plateau or Jemez shield, cut here by Frijoles Sandia-Manzano Range although it does cap the highest Canyon-1,000 feet deep peaks in the Sangre de Cristos. The Desert Plains associa- 6. San Miguel Mts. (elev. circa 8,000 feet) tion or Lower Sonoran life zone barely extends into the 7. White Rock Canyon, about 1,000 feet deep below southern part of the Albuquerque-Belen basin. rim at circa 6,500 feet The three main types of vegetative cover are grass- 8.