The Collaborative International Dictionary of English v.0.48:

Upturn \Up*turn"\, v. t.
   To turn up; to direct upward; to throw up; as, to upturn the
   ground in plowing. "A sea of upturned faces." --D. Webster.
   [1913 Webster]

         So scented the grim feature, and upturned
         His nostril wide into the murky air.     --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

upturn
    n 1: an upward movement or trend as in business activity

Moby Thesaurus II by Grady Ward, 1.0:

117 Moby Thesaurus words for "upturn":
   access, accession, accretion, accrual, accruement, accumulation,
   addition, advance, aggrandizement, amplification, appreciation,
   ascent, augmentation, ballooning, bloating, boom, boost,
   bottoming out, broadening, buildup, business cycle,
   business fluctuations, bust, capsizal, capsize, careen, clamor,
   cock up, convulsion, cooling off, crescendo, crisis, culbute,
   culbuter, depression, development, downturn, economic cycle,
   economic expansion, economic growth, edema, elevation, enlargement,
   expanding economy, expansion, extension, ferment, flood, gain,
   greatening, growth, gush, high growth rate, hike, increase,
   increment, inflation, jump, keel over, leap, low, market expansion,
   mounting, multiplication, outcry, overset, overthrow, overturn,
   peak, peaking, productiveness, proliferation, prosperity, raise,
   recession, recovery, revolution, rise, slope up, slowdown, slump,
   snowballing, somersault, somerset, spill, spread, subversion,
   subvert, surge, swelling, tip over, topple over, topsy-turvify,
   topsy-turvy, trend upwards, tumescence, tumult, turn a somersault,
   turn over, turn topsy-turvy, turn turtle, turn up,
   turn upside down, turnover, up, upbend, upcast, upcurve, upheaval,
   upping, upset, upsurge, upsweep, upswing, uptrend, waxing,
   widening